My ex wants me back after 2.5 years…

In 2020-2022 I dated my first real gf for my first 2.5 years of college, and she abruptly dumped me. She was the best girlfriend I could have ever asked for, and I will admit there were times I did not match her effort. I heavily blamed myself for the breakup, allowing myself to improve from this life altering situation. No contact as well. A month or two later she has already started dating another guy who I imagine was partially the reason for why things ended the way they did. 4-5 months after things ended, we ended up getting accepted and transferred to the same college (total coincidence, we have the same major lol) She dated this mystery guy for about 2 years and they have recently broken up. However, while they were together, I ended up being placed in a class with her, where she proceeded to not say a single word to me the entire semester. Recently she followed me on instagram and DMed me essentially wanting me back now that she’s broken up with him. (Seems fair to me right? Lol!) But I did find myself looking back on some of our old photos and thinking about her. I don’t know exactly how to approach this situation, because I don’t want to go through the pain and possibility of going through a breakup with her again; but I also know that my lack of motivation during parts of our relationship were my fault. However I can’t help but think about why she brings this up now?? I am a much different person then I was then, and I know for a fact that she is to, but I know that could also mean that she is not the sweet girlfriend I met and dated as a freshman in college. I don’t want to ghost her outright, but I also don’t necessarily want to open this HUGE can of worms. I know they all say that “they always come back”, but I never believed it one bit until now. Does anyone have any advice if they have been in a similar situation?