I am glad that you did your time and learned from what you did. I am also "proud" (in quotes because I don't know you but being a mom a I have a special place in my heart for younger people) that you sent a note apologizing - that couldn't be easy and sounds like it was heartfelt.
As far as accepting your apology and forgiving you - for some people it can be very difficult. That part is not your fault. To me you did what you could at this point for the people you hurt. Providing a heartfelt apology is what you can do. Also, to me the forgiveness side really impacts the victim more than the one the caused the grief. Yes, it would be nice to mend fences and be forgiven by them - but in the end if they cannot forgive it hurts them.
The best you can do is to do no more harm. And to give back any way you can. Instead help out at a shelter, take in a rescue dog, give donations in the form of dog food, money or time. You could also give a donation in your former neighbor's name if that would help. You don't even have to have your name on it at all so the neighbor doesn't know. Those sorts of things may help you.
Yeah you might have been a kid who acted very badly, but be a great adult that gives back. And let it go what you did before - you spent a good amount locked up you paid back to society and learned from your errors. Best of luck to you and good thoughts for your future.