Friend, a cheap pocketknife only costs like 15 dollars you can go help one of your neighbors with something for like 15 dollars
I know you don't go to my school, but as I said, nobody's going to search your bags. If you buy your own knife, you won't get in trouble
plus if someone at school for some reason decides to search your bag, you can say that it's for practical usage, and you were planning to go camping or something.
What if a woman attacks you, or even worse a "trans woman"? Plus, as a male myself, I can tell you that if I got into a fight I'd protect my testicles. A knife for self-defense is 100% worth it in my opinion.
If it's a swiss army knife or leatherman or something you're carrying, you can say you weren't planning to use the knife as well.