Being 26 and single in a town full of white trash whores I often encounter this conundrum. Firstly, more information is needed than just that you're feeling one another. How old's the kid, is the father in the picture, if so what's the relationship like between him and the mother and child, what's the mom's situation like (is she looking for a dad for her kid), have you met the kid?
If her and the father have a mature relationship, meaning he pays his support and makes his visits but understands the custody agreement and doesn't have any leftover longing for the mom that's one pretty big hurdle you don't have to worry about. Regardless of the answer to any of these questions dating a single mother should never be taken lightly, it's not just a commitment to her but also the kid obviously.
Don't you think if she wanted a father figure for her kid that she would have told him she had one upfront? It sounds to me like It's the complete opposite of what everyone is suggesting. She probably felt embarrassed to tell him and that she was afraid she would lose you had she told you from the beginning. To me, that's a good sign. She wants a relationship and she doesn't want her kid to get in the way.
Not that you shouldn't ignore her child all-together. I think you should meet her kid at least and show that you're not scared of children. You do NOT have to be It's father, but establishing a relationship is not the end of the world.
I've never dated a girl with a kid, but I get the feeling there's a lot of young mother's out there that have made a mistake and are being chastised for it endlessly. A lot of guys are probably missing out on some great women because of some stereotypes. Everyone in this thread thinks she's a gold-digging whore, which could be true, but what if It's not?
It's kinda sketchy she waited awhile to tell you. Kinda like waiting for you to catch feelings so when she tells you it'll be harder for you to just stop seeing her unlike if she told you from day 1. Maybe the fact she never told you means she's not really looking for anything serious tho and just looking for someone to go out with and have some fun. Anything with a kid that's not yours has potential to be messy