Most Helpful Girl
She wasn't there for you. Don't lose something good over something that USED to be good. Obviously things have changed, and the both of you have changed. You would never be able to get back into that relationship without feeling the constant doubt that she's going to leave you again. And that doubt comes from good reasoning. College is so different from high-school, its a lot more serious now.
You're definitely a very sweet and nice guy who's fully capable of looking for a relationship of his own. Don't go down this road again.
There's a chance she's just crawling back after something bad happened with her previous relationship, or whatever might have happened. Either way, that's drama you definitely don't need in your life.
Don't overthink how great things used to be. Think how great your life is now, and how to progress from there.
Most highschool relationships don't last long distance, call it a good run and allow both of yourselves the benefit of growing up. If it really is meant to be, it will happen after time.
Don't make rash decisions based on her guilt and remember that she didn't even have the guts to be straight forward and tell you she was ending things with you. Remember that she never gave you a good reason to end things, nor has she given you a good reason to get back.
She's not as perfect as you are imagining. Your life is good now.
Don't get played man.
Most Helpful Guy
Since I'm a really caring person and the type of guy that would always give anyone a second chance, I would say "if you really, really love her so much, then go for it if that's what your heart tells you"...
... but then you said that it was HER FRIEND who contacted you.
She didn't even had the guts to say it herself.
I've never ever been in a relationship, so I'm not sure if I'm qualified to give advice. But if she's doesn't even have the courage to say personally the three things you need to hear to know someone is trully regretful about something ("I'm sorry", "It won't happen again" and "What can I do to fix this?") then I'd rather think she just wants what people call a "rebound". She went with the other guy, got dumped and now she's coming back to the place she felt good in the past.
You say you're in another relationship. First of all, does the first girl knows this? Maybe she still thinks you're single and that's why she asked this... or rather sent someone to ask that. Maybe if she finds out, she'll respect that and leave you alone.
Also, you don't really said much about your current girl, but I would assume a best case scenario in which, even if she's "missing" some things the first girl had, at least right now she loves you. Would you think it's worth breaking the other girl's heart? And if the answer is yes, before you leave her ask yourself a final question: Don't you think you're acting like the first girl did?
If things aren't really working out with the current girl, that's a different story. Yes, you can leave her, but can you say without a doubt that the first girl won't go away again? Like I said, she didn't even had the courage to speak to you personally, so I'm not sure she's really feeling guilty. But if you trust it won't happen again, then go for it, buddy.
Again, I've never been in a relationship so I won't really tell you what to do. But I hope I gave you enough insight to decide either what's truly best for you, or rather what you really want to do.
Good luck :)