My ex boyfriend was 33 when I started going out with him, I was 20. (We were together for 2 years). At the time, I had just gotten out of a 4 year, live in relationship. I was very mature for my age, and I was looking for something more serious, than I could have had with guys my own age then. That is not why I went out with him. In my situation, it didn't work, cause he had a lot of baggage, got burned and didn't want to commit. Our interests were very different. The problem was our interests and our friends, we couldn't hang out with each others friends. He thought my friends were babies and I thought his friends were like older than my dad!
In your case, you have kids.......this is why it could work, having kids makes young people grow up fast, and if you both like each other....go for it, who cares how you met, (I have heard of weirder stories!)
Just be careful, and really get to know each other first. (not because of how you met, I think this works best in any relationship, speaking from experience.)
It is better for you, to be happy, and your child could have a "dad" in her life, than you being alone, miserable and raising your daughter alone.
I hope it all works out for you.
Take care, and you must have alot of will power, having a baby at 17, and making it through nursing school