Should I confess my interest or no ?

I really like this guy that I use to work with. He is much older than I am. I am 25 and he is 46. Yes, it's a major age difference but for some reason I really like him a lot. He use to be my manager before I switched departments and almost everyone knew about my crush on him. My friends would tell me to tell him how I feel but I wouldn't do it because I always believed that if a guy is interested in a woman, he would make the first move. To make a long story short, he got a better job and doesn't work in the store anymore and I haven't seen him much lately. I really regret not telling him how I feel because I have these "what if" thoughts running through my mind. Should I tell him how I feel the next time I see him or should I just let it go because it's not like he was totally clueless?