I have had a crush on a girl for 7 years

I've liked this girl since I was 18 and am now 25. We were good friends for years but I never told her how I felt. I always thought I would have plenty of time and would tell her eventually, but now I think I have missed any chance of ever being with her. We haven't talked in about 4 years and I kick myself every day for not following my heart and just telling her.

I honestly think of her every single day. She is the epitome of everything I have ever looked for in another person and is not comparable to any other girl I've met. I miss just talking with her and am grateful I even had the chance to meet a person as amazing as her. I feel almost like I have lost my only chance of living a happy life. Is it too late for me now? Am I obsessed? Crazy? In love? Why can't I get over her and what should I do about it?

I have been in love with the same girl for 25 years and I have finally been with her (although it's complicated) and I am now 40.
25 years of wanting to be with her and wondering if I ever would get the chance. Finally I told her and I was with her just a few weeks later.
So I would say no, you are definitely not crazy. Tell her as soon as possible, otherwise you will kick yourself for the rest of your days.
Trust me...

I wouldn't spring it on her out of the blue after having no contact for 4 years, that might scare her off.
Instead get in touch, suggest meeting up to catch up, take it from there! See if there is any chemistry, flirting etc and treat it like first dating any other girl.