You're right, she did wait a long time..
Honestly, I think if you read your own question, you already know the answer to everything.
It's a HUGE step to move to another state and get involved with someone let alone with someone who has children. Plus as you already said, you don't have a career per-se at this point. You're back in college yourself. You both are so young still, with your whole life ahead of you both.
I don't know what all she knows or what you have talked to her about. But as someone looking in to your situation who is not personally involved. You do owe it to her to be 100% honest. And that includes your concerns of the children, leaving your home state etc. If you both are willing to wait it out and see what happens, as perhaps once you finish school or get established with a job etc. you can go from there. But if you feel in your heart that you can't never move there, start with an already made family (and they are the hardest relationships to have). Then you need to let her go and you both move on. Yes, it would hurt you both I'm sure, but it's best to know now vs spending more time avoiding what will eventually come sooner or later.
It doesn't mean it has to be good-bye forever, if you both are really meant to be, then maybe one day you both may be free and can start over, as things change.
So you only really need to decide (together) can you both continue the long distance until (hopefully) something may change. Or should you move on with your life and her with hers and remain friends.
I can't personally give you an answer of which way to choose.. but if you are not willing to move there.. and you are really unsure about the children.. then you know what you need to do.... It doesn't make you a bad person.. I'm sure you have had great times together and wonderful memories. And it's best not to let kids get too attached, especially if you're not ready to be a father to them. It's a huge responsibility for anyone.
I hope this helps and gives you some things to think about.. If you need anything else please feel free to ask. If you found this helpful don't forget to click the *ACCEPT* button and please take a moment to leave me *POSITIVE* feedback.