Family Matters- Mycroft X Child!Reader

  After John had gotten married, to Mary, Sherlock deiced he needed someone he could care about as well. He went to the adoption agency and adopted a 6 year old girl named (y/n) who had (h/l) (h/c) hair and bright (e/c) eyes. She was quiet and mostly kept to herself, and she hated to get in to any kind of trouble with those appointed over her. 
  It had been almost a whole year since the day that Sherlock had brought his daughter home. Mrs. Hudson home schooled her during the day, as long as Sherlock agreed to quit shooting her bloody wall. When she wasn't schooling with Mrs. Hudson, she was drawing, reading, or taking deduction lessons from Sherlock. Every weekend, John and Mary would come over. Technically, John and Mary were your Aunt and Uncle now. Grandma and Grandpa had agreed that John should be treated like a son, and it just stuck. You also helped Sherlock when he was working on cases as well. You would help him think by handing him his box of nicotine patches and his phone or case files if he was to lazy to get up.
  One day, Sherlock's phone started ringing in the middle of one of Sherlock's deduction lessons.
 "It is Uncle Mycroft, Daddy." You said simply, without looking at his phone. Sherlock smiled and handed the phone to you. You always answered it if was Mycroft. 
 "Hi Uncle Mycroft!" You said cheerfully.
 "Hi sweetie. I was wondering if you and Daddy could come over for a dinner party tomorrow evening at 5?" Mycroft said, obviously smiling on the other end of the line.
 "That sounds wonderful! I will ask him if we can go!" You cheered. You turned to him, eyes beaming with happiness. 
 "No, (y/n)." Sherlock sighed.
 "But Daddy!" You said, making your best puppy dog eyed face.
 "Oh okay, just this once!" Sherlock smiled.
  You turned back to the phone,
 "Uncle Mycroft! Daddy said we can go!" You grinned, the excitement just spilling over in your voice.
 "Great! See you at tomorrow 5 darling!" Mycroft smiled. You hung up, handing the phone back to your daddy. You climbed back up into this lap and asked,
 "Why don't you like Uncle Mycroft?"
------------------(The Next Day At 5 In The Evening)------------------
  Sherlock knocked on the door to Mycroft's estate. Your Uncle opened the door almost instantly.
 "Mycroft!" You grinned. Mycroft smiled down at you and ushered you in. The floors were hardwood and plush white carpet and the walls were white, except in the dinning room. In the dinning room they were the beautiful emerald color that lighten up the whole room.
  There were tons of people at the dinner party. Grandma, Grandpa, Uncle John, Aunt Mary, several close friends to the family, Great Aunts and Uncles, about 10 cousins, all of which were in there 20's at least, and there children. The table was covered in some of the most yummy looking food you had ever seen. There was roast turkey and pork and mashed potatoes and several other foods that you couldn't name. 
  Mycroft always enforced table manners, which you found out the hard way. Your table manners, to be blunt, were absolutely horrid. You had a habit of stuffing your face like you would never get any food ever again, which you developed when you biological parents forgot to feed you for a week. You were about to take a huge bite of pork when Mycroft glared at you. Your eyes went wide and you took some of the pork off your fork so it was a respectable bite size. Mycroft smiled at you and went back to the conversation. You should have not chosen to sit in between you father and Mycroft, as they kept glaring at each other and you throughout the conversation. Mycroft caught you trying to stuff your face about 5 more times before you finally deiced it wasn't worth it. The conversation between the adults was dull to you to say the least. It was stuff you already knew or wasn't any concern of yours.
 After dinner was over, the table was cleared and desert was brought out. There was cake and cupcakes, ice cream and cobbler. You could have eaten it all with your sweet tooth but you were scared Mycroft would look at you disapprovingly again. Sherlock put a cupcake and a small bowl of Ice Cream on your plate and you were trying so hard to just eat all the ice cream in one bite. Then, it came to the cupcake. You wanted to eat it but you also didn't want to get frosting all over your face like you always did. You picked it up carefully and tore half of the cake off of it and put it on top so you wouldn't get frosting everywhere.
  Mycroft reached for a second piece of German Chocolate cake and Sherlock scoffed. You elbowed your daddy in the side and he looked down at you. You just smiled innocently back up at him and he frowned and went back to talking with your Great Aunt Sally. Mycroft frowned and stared down at his plate before deicing that he deserved some ice cream. Sherlock laughed at Mycroft and it very quickly turned into a shout fest. They both stood and started shouting insults at each other, some of those insults they said in a language so you wouldn't understand them. Mycroft thwacked Sherlock on the head with his umbrella and stomped out of the room. Sherlock smirked and sat back down. You slapped your daddy on his arm and ran after you Uncle Mycroft.
  It took you a while to find him. You walked down several halls until you saw a room with the door slightly cracked. You opened the door slowly to find a very distraught Mycroft sitting down at a desk, his head in his hands.
 "Uncle Mycroft? Are you okay?" You asked as you walked up to him. He looked up at you, his face was red and his eyes looked tired, puffy, and old.
  You climbed up into his lap and hugged him,
 "It's okay. Daddy can be mean sometimes. He is just jealous that you can eat more cake and ice cream than him." 
  Mycroft laughed and hugged you back,
 "Yeah, I guess so. If he ate that much he wouldn't be able to move for weeks."
 "Your not fat, Mymy. You shouldn't care what other people think of you either. Just be you and that is all that matters. It doesn't matter how much sweet stuff as you eat as long as you don't do it every single meal." You said, leaning you head on his shoulder. Mycroft nodded and you smiled,
 "You know what, family matters. It is all we have in the end, no matter how badly they treat you. Wait here." You got up and ran down the hallway and found Mycroft's secret umbrella closet. You randomly grabbed one and walked back into the dinning room. You grinned as you entered the room. You were using the umbrella like a cane, the same way Mycroft did. You strode strait up to your father and almost dragged him into the room were Mycroft was.
  You forced Sherlock to sit across from each other. You shut the door and guarded it so they couldn't leave.
 "Now you to are going to make up and tell each other sorry." Sherlock rolled his eyes and got up and stepped up to the door,
 "This is ridiculous, I am leaving." You took the umbrella and smacked Sherlock as hard as you could. He stepped backwards in surprise.
 "No, you are not leaving 'till you make up." You stated.
 "(Y/n)..." He threatened.
 "I don't care if I get in trouble. Now sit!" You said, raising the umbrella as if to smack him again. He sighed and rolled his eyes. He went and sat back down in front of Mycroft. They sat down there for a while, just staring at each other.
 "Mycroft, I am sorry that I have made fun of your diet and how much cake and ice cream you eat." Sherlock sighed.
 "I am sorry for screaming at you in front of our entire family," They both said at the same time. Then, they just sat there staring at each other again.
 "I'm sorry for not being there for half of our child-hood." Mycroft said.
 "Oh, your really not going to bring that up in front of (y/n) are you?" Sherlock huffed.
  You plugged your ears as if to say,
 'Hey I'm just here to make sure your friends again, don't mind me.'
  Sherlock sighed and mumbled,
 "It's okay Mycroft, I understand why you had too." Mycroft raised an eyebrow.
 "I understand. You were working towards your future and I was a pretty annoying little brother I admit. I found things to do by myself." Sherlock said.
 "Sherlock, I am sorry. I should have put my stupid future aside and made more time for us to be brothers."
  They both stood and hugged. Mycroft and Sherlock actually hugged each other.
 "I love you Sherlock." Mycroft said.
 "I love you too, Mycroft." Sherlock smiled. You stepped aside and opened the door. Mycroft picked you up and kissed your forehead and carried you all the way out to the dinning room.
  You sat in Mycroft's lap throughout the rest of desert and Sherlock took your seat instead so he could sit next to his brother.

~~~---~~~Extended Ending Y'all~~~---~~~

  Sherlock's phone went off and you both said at the same time,
 "It's Mycroft!"
  You both dashed for the phone, both of you wanting to answer it first.