Am not sure what's you put all, did you refer to how long you invest to learn Bitcoin or you're used all of your money which is $450 to buy Bitcoin? As long as you can afford to lose all of your $450 and you don't need to use that money to buy stuff in your school, you're good to go.

Does you mean this app? https://www.stockpile.com/

It's a centralized platform and I see they're ask KYC verification, it's not good for long term holding, you need to use hardware wallet since you're still newbie. Make sure you bought it from official store/seller. Anyway this thread is good to learn Security and Privacy Topics on Guides and Protection.