Right out of high school I had the same thought you did. But then I thought of some of my close friends that had a kid and realized "I sure wouldn't want people to not go out with them for that reason" and that pretty much changed my thinking overnight. I've dated two people since with a kid, and came pretty damn close to getting engaged to one of them. Of all the people I've ever dated, those two were the best of the bunch. It takes a great deal of compassion to be a good parent, and that "usually" transcends to their personality as well.
The question is more on you, and how do you feel about kids. Even if they have a dad in their life, if you were to get married to this person down the road, it becomes part of your life too. Understand that and search yourself. If you don't want a kid in your life or don't want to deal with it, don't lead her on, and cut it off early, because you then essentially have two people falling for you(her and her kid). But you may find out like I did that it didn't matter one bit. If you really care for her, it's just one more thing to love about her. Don't let it scare you away. Good luck.