Upfront. You were correct when you used that word.
Here's some advice, and I hope you're paying attention, and taking notes.
You MUST let her know that you like her. And you MUST do this as soon as possible, preferably the next time that you see her. You MUST do this because life is short, and before you know it she will be gone, taken, spoken for, along with any chance of you and her ever being a thing ever.
You should just say, straight up, that you like her and that you want to go on a date. Yep, just like that.
She might say no. Suck it up buttercup, that's the romance game... but you have to play it. You may have to hear "no thanks" a thousand times, but it will all be worth it. That's the way it is for most of us, who are not super-beautiful demigods surrounded by potential partners. It's not easy. Even if she says "no thanks", she will most likely respect the fact that you are someone who speaks their mind, that is admirable.
Do not "give it some time". Next time you see her, tell her that you like her, and ask her on a date. Leave no doubt about it. You have to understand... you HAVE to be willing to make a fool of yourself. Women want someone who is willing to risk being a fool for them. They are looking for that. If you want it, you have to be willing to do that, and smile and move on if it doesn't work.
Like I said it isn't easy, it requires some courage and self-confidence, but I promise you, if you can do that, then it will pay off big time.