I have a nagging Dilemma.. Please help( Ladies & Gents)!!?

...So, Here's the situation at hand. I'm a 28 year old female who has never dated before due to lack of self esteem. I am on the heavy side and that is the underlying problem, but it seems like it's only a problem for me because, there are guys who find me attractive and has even referred to me as being y( which I tend not to believe.) My self image is horrible, so much that I have a hard time accepting dates or pursuing guys. Like for instance; I have a My-Space page, and I have guy buddies on there who comment on my pictures and tell me that I'm beautiful, y or cute and they undoubtedly see that I'm heavy set and they still continue to pursue me. When they tell me these things I say thank you but, inside I don't feel that way about myself. There's one guy right now who wants to get to know me better, and I'm interested but I'm also nervous. I don't give my self a fair chance. So I told him to give me his number he did and told me to call him whenever. he seems nice, any advice?