Read first paragraph for story, second for

Basically I have this girl I fell in-love with waaay back in like 9th grade but we stayed just friends... Which was completely my fault, she had feelings for me but I ended up making out with her best friend and we didn't talk for awhile... now its our senior year and we talk pretty frequently and when i was really drunk it slipped out to her best friend that i still have feelings for her. Anyways she has a boyfriend of like 8 months but even after she found out that i had feelings for her she's still inviting me over for her birthday tonight to watch a bunch of movies. Should I continue to be the best friend to her or pursue a relationship with her and be honest about my feelings? If I was to tell her about my feelings, I would do it in such a manner basically telling her I wouldn't want to hangout with her anymore because I don't want to conflict their relationship. Or anything that basically says, "Hey! I have feelings for you and I think you do too but it's not right for me to do anything when you have a boyfriend."

Or any advice on the situation?
Basically;
I'm 17
She's 18
We've been 'best friends' all senior year plus a little of junior but she still shows IOI's a lot.
When she wanted me a while ago in tenth grade, I made out with her best friend.
She has a boyfriend of 8 months
I want to tell her I have feelings for her, or at least try and pursue something with her instead of being a 'bestfriend'

dont tell her you have feelings for her, it wont happen