What grade level? What kind of application?

Criteria is already plural, doesn’t need an -s on the end.

I am assuming you re referring to college. It is up to you as to what you feel comfortable with. A larger university will sometimes have freshmen math classes of 300. A smaller might have 50 (as is the same with other entry level classes). Do you feel more comfortable “lost in the shuffle and do not need the extra help”. Do you want to get to know all of your peers in a given setting. Once you get into more of your specialized classes for your major the classes will be smaller for the most part anywhere you go; thus, your first couple of years are based in the class size question.

The more important question is where do your think you want to focus your studies and which university is best suited for your area of study.