How to deal with helmet hair

So I'm 15, and go to high school.

My hair is medium length, and either looks really good or awful, there's no in-between.

I'll do my hair at maybe 7:20 and leave for school at 7:45, for a 15 minute bike ride with a skateboard helmet on riding a bike.

Doing this causes my hair (Even after hairspray and brushing, hair drying everything) to get flat.

I do use conditioner every night (it's curling conditioner, because I thought maybe it'll make my hair get slightly curlier, it's currently wavy-ish.

Basically, my hair when flat looks like a school shooter, and that's bad. r/Hair, help me figure out what I can do to prevent this.

((I'm sure someone will say to do my hair at school, but there are no mirrors in any of the men's bathrooms. I also have very little time from me arriving at school to when it begins, at least not enough to wet, style, and spray my hair.))