Alright so i`m just a random guy that joined this group recently but i`d love to help if possible.
To start with, you've got to know where you're standing since she might already see you in a certain way; it may depend on how flirty you might`ve been overall till now with her, if you've given her any signs of this and, if so, how she may have reacted to them. Thing is you've got to see the situation as clearly as possible to take logical decisions rather than fully emotion-based, so she won't think of you as sort of "too much" even if your intentions are good and caused by strong emotions, since you might not see it the same as she does.
Try to keep your calm as much as possible and to show her that you care more than tell her; you two must be close already, but have you ever done anything that would come closer to being romantic rather than simply hanging out with friends? If yes, then that helps a lot with the confession since something has built up over time cause of it; if not, however, then you Certainly should try to start by asking her out and sort of give a hint rather than just go to her and confess. Confessions are supposed to be more of a climax that makes a strong bond of friendship go to the next level aka a relationship (the best friend partner is what is the best kind of partner in my opinion).
Try to show her what she'd get into if she'd be with you through the smallest things; from showing appreciation through telling her how you feel when you're with her to spending time with her and have fun in the best way you think you two would (watch a movie or play a game she might like or so; show interest in things she likes but be opened to what you do as well if she asks).
Overall you've mentioned knowing each other for a decent amount of time now, so i think it shouldn`t be too bad as long as you two are close; just make sure you do Not force it and let it go naturally since that way it will feel better for both instead of something that would lead her to feeling obligated or so. (I do not know you but no one deserves that and always keep in mind you have just as much to give as you think you'll get from being with her or, in other words, you're equals in it).
Best of luck dude!