I like my best friend

That's a tough spot to be in @SerchMc04 :(

If those deeper feelings are faily recent I would advice you to keep it low profile first and scout out your chances.
Maybe it wouldn't be as weird to your friend as you'd think, maybe it kind of would be. It would be better to dip a toe in the water first to try to find that out.

If it has been going on for a long while however, I would advise you to be honest with your friend. Share your feelings about both having feelings for her as well as being afraid that it will ruin your friendship. It might make things a bit weird between you two, but I'm sure your friend will appreaciate the honesty. And who knows, maybe she even likes the idea of you two becoming an item. If not, at least the secret is out, if nothing else that will relieve some of the stress.

Best of luck to you 💜