Can I wear heels to school?

Well, technically you could, but I would advise against it. I mean, do you really want to be walking around school, hauling your books and backpack, with four inch pumps? No, try wearing them when you go out shopping or anywhere, really, where you're out and just having fun (I'd even carry a large purse with me and then have some spare flip flops in there).

From being around a bunch of girls I would advise not taking your prom shoes to school. Walk around in them for a day at your house you don't want anything to happen to them and you maybe don't want everyone knowing what they look like before prom.

How crowded are your school's hallways? That sounds needlessly painful and awkward, and could end horribly (and may be against your school's dress code, though I assume you've checked that already). Can't you just wear them on a weekend or something?

As long as it's not against school code, yes. Girls at my school always are wearing heels of various sizes from tiny ones to monstrous ones.

yes, you can

but why would you? school is probably different from prom. you'd have to climb a lot of stairs, wouldn't you? your feet would be so sore in the end.

Only if you are male

yup.