@dfoster85: Most grocery and drugstores will gladly exchange one size of diapers for another. Many are even willing to exchange it with no receipt as long as the package is still unopened! You'd be surprised how often someone getting the wrong size diapers happens!
@ElizaBennett: It is all right to use diaper cream with cloth diapers. As long as you a) don't smear too much of it on (you actually only need a thin layer) and/or use a liner.