Can you defer admission to take a year off and apply to other colleges?

I got in to a university but the deadline to accept offer was on may 1st. I planned to apply to other universities as well and their deadlines are until july (admission decisions are until september). I had no other choice but to accept the offer just in case I did not get in to the other universities I’m planning to apply. Will I be able to defer admission to take a year off and meanwhile apply to other universities? If other universities I’m planning to apply happens to accept my admission to those universities, will I be able to cancel my admission to the university I decided to take a year off??