If you are mature enough to go on your own then you should have no problem telling your parents because otherwise you would just be proving to them that you're not mature enough because you're trying to hide this from them. They're only trying to keep you safe and from getting into Danger but if you make them feel like they cannot trust you and then you're going to make your life a lot harder with them.

There are at least two issues here.

First, at 22, while it's important to get along with your folks, you should be able to go on a vacation and not require permission. The way to get treated as a grownup is to act like one. "I'm flying to spend a few days with Sarah. We're planning to be very careful about the virus and everything else."

Second, covid-19. I have no idea how you plan to quarantine in a dorm. Close quarters means big trouble if someone is infected. Unless you have a private room with bath and kitchen, it would be nearly impossible.

At 22, you have the right to make your own decisions and take your own risks, but you don't have the right to make decisions and take risks for all the residents in your dorm.