I need help

All あなた need to wear is a large シャツ that covers your panties. Thats it :P
....By that I mean あなた can wear anything and it wouldn't matter much ;P Wear what feels comfortable.

it might be hard and difficult,

Here's your solution.

Just dress casually. Some jeans and a red または ピンク shirt. Don't stress over it. If you're calm, you'll have a good time.

One thing あなた don't wanna do is dress half naked.
Don't have あなた boobs all out and crap.
Wear what ever is comfortable but classy, ya know.

wear a 上, ページのトップへ hat, monocle, cane, just kidding just kidding

wear whatever あなた feel comfortable in, don't stress over it, if あなた wear something uncomfortable you'll be too busy trying to get comfortable that あなた won't be able to talk to him! If あなた want some real ideas maybe ask some other people that are going what they're wearing?