How long does it take for an adoption to be finalized?

I am getting adopted. And at this time I have some paralegals who are working on getting my adoption approved. And we just started looking for info on it on April 21st. I am hoping that it gets finalized in the next year or 2. Do I need to show up to get my adoption finalized? Is it just my last name that is going to change or can I start using my adoptive mom's middle name? Will I be getting a new Social Security Number?