Do nike's baseball mitts run big or small?

i play 2nd shortstop and 3rd and need a new mitt. I have an 11.5 mizuno but its real old and worn down. im looking at a nike diamond elite series 11.25 w/ I webbing and an open back. this might be to small. but i dont know. im also looking at the same version just the pocked is w/ T webbing and thats an 11.5 what should i do?