Everday in class im forced to sit next to this girl and normally i dont have a gag reflex but omg she puts on so much perfum its like a biohazard i cant even breath cause its like stinging me
Because it makes you smell better (arguable) and that leads to you being more confident, as well as potentially looking for compliments/attention obviously. But if this is a real problem then you should ask teacher if you could sit somewhere else or overall tell them about this problem. They would understand and do something about it.
I would suggest going into story that has good selection of them (not just some grocery store that have some cheap ones unless your on a budget). There's just a lot of difference between fragrances when it comes to smell, projection, price, longevity. Best is to test different ones in store and then read maybe experiences and then order one online because its usually slightly cheaper. Esp if you are actually spending bit more on it.
Something like Dior Sauvage(like the guy said) is really popular and liked. I personally use Dior Homme 2020 that is pretty similar. Ones that smell similar to those are really versatile and good everyday wear. Versatility is something you should consider as well.
But I would suggest you testing ones yourself or watching YouTube videos about it or reading online like I did.