So I just started dating a baby mamma.

Ok, now that that's sunk in, I'll say that she is a very kind person who cares a lot for her kid. She works hard, goes to school and has a tangible creative career pursuit. We've been on a few dates and fooled around a bit, with me later discovering she had a large N-count (mid 20s and she's 20).

I really like spending time with her and she texts me pretty often (which I like, because other girls I've seen are so distant) but I'm moving out of the city in a few months. I'm fairly sure she's getting really into me, but I don't have plans to help raise this kid or stay in my city.

In my city, in my experience, dating is pretty shit (Even my very alpha friend agreed). I've still been able to secure some good looking dates, but none put in any investment forward after initial few dates. I wouldn't say this is oneitis because I've been dating around, I just don't want to hurt her and I'd like to keep this dating going until I leave, if at all possible.

tl;dr: How do best I bring up to a caring baby momma that I'm not going to stick around for too long?

EDIT: I can see evidence of oneitis. Updated tl'dr.