Your Dad is Captain America

Growth Spurt

—— Your POV ——-
Your whole body hurts and it feels like someone is pulling on each limb so bad you cry. "Daba?" he wakes up, "You said your first word, Y/N." "Daba ib hurs." "What hurts sweetie?" "May boby." "Your body?" you nod, "Bruce!!!" the man named Bruce comes, "Steve, what's going on?" "Y/N is in pain and she's talking, is she having a growth spurt?" "Daba, ib hurts." "Her english is getting better, she's having a growth spurt. It must be the serum." "Daba, it hurts. Mak ib stob." you sob, Bruce says "We can give her a pain reliever but that's it." Daba nods, "Baby, it's gonna be ok." you nod, holding onto him for dear life.
—— (time skip) ——
You wake up a few hours later, your Mom says "Hi honey, Daddy said you had a rough night." you nod, "I dwid." she nods, your Daba is sound asleep. So your Mom carries you to Bruce.
Bruce walks over to you, taking your height and weight. Your body is now that size of a three year old but your brain is developed to that of a six year old. You finally manage to get your mouth to work with your brain better and your English speech skills progressed. "Bruce?" his eyebrows raise, "Is Daba ok?" "He passed out again, Y/N, he just needs some rest. He's going to be ok, Y/N, it's a lot for him to process." you nod, your body growing again. You're now about 4' 5" and Bruce hopes that your growth spurts stop for a bit.
Your turn to see your Daba in a wheelchair, your Uncle Bruce had told him to rest and if he dared to walk around he'd confine him to a chair till he saw fit he was rested enough to not pass out.

(Here's one I found online, please don't judge)
Your Daba sat there, dark circles under his eyes, he looked terrible, that if he stood he'd fall. You understood why your Daba was in the chair, it's because when he passed out, it was bad.
Your Mom pulled the chair closer to you, "Dad?" "Hey honey." "You look bad." "I know, baby, I'm not feeling the best." you nod, you wish there something to help make your Dad feel better but there wasn't much. Your Mom picked you up and sat you on your Dad's lap, "I'm gonna get better, baby girl, I promise." you nodded, then Uncle Bruce spoke up, "I looked at tour blood samples, Steve." "And?" "Hydra managed to make a drug that weakened the serum with the drug they created." "Is it permanent?" "It's like a virus, so it's gotta run it's course, but honestly, I'm not so sure. We're gonna take this day-by-day." your Dad nodded, "But it's also affected your body, Steve, you need to rest and not move so much." your Dad nodded.
Your Dad was released from MedBay as long as he would stay in the chair to rest and not move, because if he moved too fast, they didn't want to risk losing him. You sat there listening to your Mom talk, your Dad smiled at you, "What're you thinking, pumpkin?" "It's just weird." "Want to talk about it?" You nodded, "Its strange, I can remember everything when I was at Hydra even though I was there a short time. And it's like I'm older than I am." he nodded, "Well, honey, I'm sorry that you have to grow up like this. I love you, kiddo, I want you to know that. What makes you my daughter is there's a thing called DNA and they had a bit of mine, so they created it to make you and they made this serum that helped me, and they made a version for you and then you have some of mine. So you're gonna be stronger as time goes along. And you also have Autism, sweetie, and Uncle Bruce thinks you've got a power you didn't inherit but it was created for you." you nod, you loved your Dad, he cared the best he could even since he looked terrible.