This is an answer in the guise of a question, and the answer (belief) being that the universe is finite. Let me offer a better question: is the universe finite or infinite?
What is the concept of infinity but the outer limit of our mind's ability to conceptualize?
(I don't know why you switched from "infinite" to "infinity". I am opting to answer for the word "infinite".)
What is the concept of infinity but the outer limit of our mind's ability to conceptualize?