So me and my old very close best friend haven't been talking for over a year now. 3 days ago she admitted that she was a "bad person" and that she is here for me. We started talking and remembering our memories and laughing. The next day we started talking less and like I was really excited that we are friends again. I really missed her and I don't know, I'm worried is this something serious or what? Please help I need advice. Thank you!

What's the hurry for a bunch of worry. Take your time getting reaquanted, but you don't have to be naïve about it. Just go with the flow, and see what happens. It's been a year and maybe she has changed for the better, but then again maybe not. Nothing wrong with keeping an open mind, AND your eyes as open as your heart.

Likely even though you have made peace with each other, you may not be as close as before and no need to force it either. It may never be the same as it was, and that's okay too.