Are you fucking serious? Is this some kind of sick bait or joke?
First of all, you sound like a total beta and second of all, there's no perfect moment. It's all about owning the situation and embracing the chaos, make it your own moment. It's not like your world will go to ruins if she says no, you'll probably end up as friends and then you got a chance with her friends so it's a win-win situation anyways. Also there's plenty of girls out there, why would you limit yourself to just one?
Sounds like your hormones is making you a delusional cuck and irrational. Stop letting fear control your actions and emotions. It's one hell of a world out there, you just gotta use the tools available to you in this century and from here on it's survival of the fittest. Do or die, mr fan of OogaBooga69.