Shouta Aizawa is your father and he's in the prestigious Hero academy called, UA high, he's a Second year and he's 17 years old. How is he your father at that age, you may ask. Its because he did things he shouldn't have done when he was younger and he got your mother pregnant at a young age with him too. And so your mother talked to your grandma AKA Shouta's mother, and they both made an agreement, your mom would give you up and leave you with Shouta, your Dad.

9 Months past you were born and so it was time for your mom to leave you with your dad, you didn't know any of it, because you were just a newborn. Once you were born your grandma took you away and made your mom and her family leave the country, away from your father. He never saw her again and was forced to take responsibility of you, he still loves you even if you weren't planned...

Now he's 17 and your 2 since you were born when he was 15 years old. Since he now lives in the Dorms, his mom AKA your Grandma was taking care of you at home with your grandpa.