Should I make contact with someone after a few years of not talking to them?

So I was just wondering if I should make contact with a friend(she was my best friend at the time). It's been about 3-4 years since I talked with her. I had to move to another state at the time, but she wrote me a note with her number on it. When I arrived at my new location I decided to hold off on talking with her(really dumb mistake). I'm not sure what it was but I would always hold off on talking to her. It's not like we ended on bad terms, but for some reason I just avoided it. Then after a few months I had lost the note with her number on it and so I just kind let it slide. Now fast forward to the present. One day I was on Facebook and just thought "why don't I look up my friend from a few years ago?" I found her Facebook and here I am. I don't know if I should try to make contact with her again or just let it go. It's been kind of bothering me since I was being a jerk and never talked to her again. The least I would do is apologize but I don't know if I should enter her life again. What do you think I should? Any help would be appreciated.