I was in your position years ago and I always made a point of bringing the fact that I had a daughter into the conversation on the very first meeting with any man I fancied for two reasons: one that if he had an issue with it then he wasn't worth getting to know and I wouldn't get hurt and two I didn't want to let them 'find out' at a later date, especially from an outside source. Men come (in more ways than one!) and go - kids are forever. Be upfront about it and be proud of your child!