I have a feeling for this girl should I tell her? Please read!?

Okay, so she was my supervisor where I was working, I am 23 and she was 2 years younger then me, but she left the job because she found a better one and after a month I quit too because of school, anyway I had a feeling for her but problem (she is married)? Anyways its about almost 6 months now that we haven't seen each other after she left but I am still thinking about her once in a while and I don't know why, I for real dreamed about her twice this month, I woke up shocked and this is what was really happening, she comes in my night dreams sometimes of how I liked her, how helpful she was and how friendly at work ( I go to college and there is girls all over, but I think she is different and I don't have an answer why)!

My question is that she is married and has one kid, but since she is nice enough if I ask her for coffee she might do it, but what should I do, if I ever see her again whether invitation, random or what ever should I tell her about all this and how my feeling was and is, and if I do what might happen?

P.S. I know she is married as said, but its really becoming hard for me. Thanks.