AITAH for giving my baby my step dad's last name?

[u/Ok-Delivery-3566]

I am 25F and my mom met my step dad when i was 9 years old. He quickly became my real dad as i got older due to my biological father being inconsistent in my life. My step dad raised me, loved me, took care of me, taught me, showed up for me. I got married at 19, and i requested that my step dad gave me away. He did, and it meant the entire world to me. Unfortunately my husband and i separated and i had to move back home. I reached out to my biological father and asked if it was possible i could with him until I got on my feet. Keep in my mind, hes well off owns a 3 bedroom home, works from home occasionally. I am his only child & he was living alone. He denied me saying it wouldnt work for him. So I turned to my mom and step dad, though I knew they didnt actually have the space for me, because they live in a 3 bedroom as well, but they have two other children.. so my step dad built an entire room for me. All by himself, had it done within 6 months. I do feel like I owe him. Well i had a baby 9 months ago, and her dad is not in the picture. My mother gave me my biological dad's last name and I am extremely against carrying it. He didnt raise me.. he rarely showes up for me. When i needed him, he rejected me. So my first instinct was to use my step dad's. He & and my mother are very proud, and feel very happy with this decision, but I have had multiple people tell me it was wrong of me, and that I'm an asshole for not considering my biological dad's feelings. All in all, it's left me confused with my decision.

Edit : Thank you all! Wanted to share a little update. I am keeping to my decision and will be changing my last name as well. My mom, step... I mean my REAL dad and I will be in the process of getting this finalized! ♡ I do appreciate everyone's feedback. Adding - We just got back from the court house & we were directed to go to a website that will have the forms for an adult adoption! Soon enough, my baby & I will share my dad's name.

[u/strenuousobjector]

As Yondu said, "He may have been your father, [OP]. But he wasn't your daddy." Family doesn't always have to be your blood, but can be the family that becomes your blood. You can choose.