I've been accepted to a school but am waiting on the others-what to do

Looking for some help and couldn't find the exact forum to put this in, so I'm hoping this one is ok.

I've applied to four schools. One of them has rolling application deadlines and the others are set.

The one with the rolling deadline already got back to me and accepted me, however it's my last choice. I have an interview scheduled for my #1 at the end of November, and I haven't heard anything back from the other two.

My problem is this-the school that accepted me said I need to pay a $200 enrollment fee and accept their offer by November 21st, which is well ahead of when I'll hear from the other schools.

What can I do about this? I'm sure it's no surprise to the school that I might be looking at other schools, but I'm not sure if I want to bring that up, as they might be like, "so are school isn't good enough that you're willing to jump at our offer? Maybe we don't want you..."

Also, I read something online that if I accept a school's offer, there's something other schools can look at to see if I've accepted any offers, which could raise questions from my top three schools I'm still waiting to hear from. I'm not sure if that's true or not.

Any suggestions? If I don't get into the other three schools, of course I'll take my number 4 pick since I've already been accepted. I just don't want to burn that bridge by saying I'm waiting to hear from other schools.

Has anyone been in this situation before that could advise?