I was thinking the same - which "should" be a huge relief to you - even if it doesn't feel that way. If anything you should consider it a lucky escape. Horrible to say it but that's how it is coming across. If that is the case consider this a lesson learned :( but move on and find the right girl for you. Try not to dive straight in and i am sure it will work out for you.
If, however, the baby is yours this can complicate things dramatically. For me i would horrified to lose contact with my children. I love my three sons to death and would sooner die than be parted with them. I can tell you have a similar attitude already - so do what you feel is right. This girl is inexperienced in life - hopefully her parents will also steer her in the right way - into a life and future with you.