How should i ask my girlfriend to prom?

I am in college and my girlfriend is a junior in high school. We are in a long distance relationship but we decided that i could visit her around the time her prom is. We both know im going to prom with her but i want to ask her anyway. I already asked her today. I wrote her a poem and put a picture of me in a tux and her in her dress next to one another then fiddled with it to make it look like it was our prom pictures. Then i said "Picture Perfect? Let's make it happen" and she said yes. But, she has this guy friend who asked her, and he did this whole scavenger hunt thing and i feel like my way didn't make her feel as special as she is to me, so i want to do it again. Bigger and better. Remember we are long distance, thats why im having troubles going all out to ask her :/ please give me some ideas..