I would just be honest with her. It's kinda obvious you both want to be more than just friends, be honest with her and tell her you want to take it to the next level. See what she says. You said the one time you told her that you 2 fell asleep shortly after so it's possible she forgot / wasn't paying attention being so tired.

I would just see what happens when you say you want to be more than friends, if she feeds you any BS then move on and stop giving her all the benefits of a relationship without any committment.

Best of luck and let us know how it goes.