Not ready for a relationship--what should I do?

There's a woman who used to be a co-worker who has been dropping hints via FB and email that she would like to get together with me. She's a nice gal and we share some interests but I'm so used to living alone and not being disturbed (I have very little free time anyway--work a lot of hours) that I don't know if I'll ever be ready for a relationship. If I open that door there may be no turning back. Should I just let her slip by--like I've done in the past--or take the risk that my quiet little world might get turned upside down?