Is telling a girl you liked her worth it?

So there's this girl I really like and I haven't really talked to her in about 7months or so (I've liked her for almost 5 years now). I feel like I'd like to just tell her I like her but I just get so nervous around her so nervous that I avoid her because when I'm around her I get so nervous and get slight shakes and start to have a bit of a panic attack... :/ but its strange because when I do run into her even if I don't talk to her it kind of makes my day :/ I'd really like to tell her I like her but I don't want to scare her and embarrass myself... What should I do? Should I tell her and risk getting in trouble for something like sexual harassment I really don't want to get in trouble. Also is walking up and telling her the proper "social protocol" or should I do something else?