I’m a teenager working at an old folks home 30 hours a week and we wear masks too!

... You should

Working at a place were the residents are all severely at risk and wearing a mask is somehow the extra thing that you're doing? That's a bit like being a lifeguard at a public pool and announcing that not only are you a lifeguard but you also know how to swim.

Being a teenager is basically mathematical code for "I don't know anything "

You mean there's even a sliver of an excuse not to?