It depends on the barn you're riding at. When I was taking lessons on school horses we didn't jump more than 2'3 unless we were leasing (and thus had to purchase our own insurance, it's a big thing in my province) or owned our own horse. That said, I can 100% understand that, and I would not expect a school string to have lesson horses jumping 3 ft with lesson kids just because it's quite strenuous on their joints, and if you have multiple people jumping on multiple days... well, there you go.
So I know a lot of the schools where I am don't do it unless you lease / own, but who knows, when you get there maybe you'll be able to find a lease! From 2ft to 3ft is HUGE leap, so think small goals for now