I think my girlfriend and I are in different stages of our lives and it might break us apart.
So what stages are you and your girlfriend in right now that are different?
I started my career earlier than her, and she's still in college.
I understand your both at different stages of your life right now. I think you need to take some time and think about this because you may do something you'll regret later down in the line. Some communication in trying to work things out could be beneficial.
But what if things don't work out?
It's possible that things won't work out, but you should try to work on them before deciding to break up. Being in different stages of life isn't that big of an issue.