So I've Put A Lot of Thought Into This (Please read, I really need your opinions)

So I've put a lot of thought into this. My name is Tori Arterburn-McCall and when I turn 18 (A year and a week from now), I'm taking the "Arterburn" out of my name, legally. It's only there because it's the only way my sperm donor (that's what I call my dad) would sign the adoption papers. My mom had an open adoption/family adoption and I was adopted by my grandparents when I was 4 years old (raises quite a few questions. "If she's your mom why do you call her Mamaw?" is the most popular) but I'd been living with them since I was 3 weeks old. My dad abandoned me and my sisters when I was four years old, and decided he wanted to be our dad again 11 years later. I'm not having it, sorry not sorry. His own brother (my mom's sister's husband) is more of a dad to me than he will ever be. Honestly, if you're going to abandon your child, don't try to be a dad when all the 'hard stuff' is over, you have 4 other kids with your new wife, just leave me alone. I don't owe him anything, so I'm not going to keep is his last name any longer than I have to.

Or am I wrong in thinking this? Opinions please?