Prom, now closer than friends?

I (18m) am attending prom with a year long friend (17m) whom I’m wanting to develop a deeper relationship with.
What should I do at prom to make “the step” to express how I am wanting to possibly begin a relationship?
We’ve began hanging alot more, and we even have matching tuxedos/dresses. She’s an extremely physically introvertive person who never hangs alone with a guy one-on-one, but we have recently been doing so. I’m unsure if I’m being super-friendzoned, or if she’s beginning to also want a deeper relationship. There are other small signs, but I may be reading into them too deep; however, she has always been a hard to read person.

So how do I got about it? I want to do so at prom in a romantic manor, I’m just unsure how to bring it up without possibly breaking the “trust” she has developed in me.

I’ve had an extremely hard time beginning relationships for the past 2 years so any and all advice would be fantastic. Thanks in advance folks.