I have a terrible predicament?

Ok I've been good freinds with this girl for 11 years now. I've liked her since I've known her. I told her I liked her 10 years ago. I live in different town but she lives in my hometown where id love to move back to. I come home every now and then and I always plan on telling her how I feel but never do in fear of damaging our friendship. I have a baby on the way with another girl but things always go south with her and I. She is from another state and I don't think she wants to live where I live anymore. This girl I like is also engaged but her man jjust went to prison for 2 to 3 years and she's not going to stay with him. She rushed into her relationship with him and it was a mess from the start. I'm going back to where I live in two days. I was flirting with her for the whole day yesterday and she flirted rite back. I don't know how to tell her that I've had strong feelings for her for the last 11 years and that I would drop everything for her. I'm all flustered and confused. I don't know what to do...