have you ever handled (even without firing) a gun? how big or small are your hands, and your fingers?
for some people, a Glock evidently feels like holding a 2x4 whereas for me it's great cuz i have giant paws. for me, a 1911-style is too skinny and my hand cramps around the narrow grip, but a beretta-style is easier. another guy i run into at the range has short fingers and has to really angle his hand to reach the trigger on a Glock, and he tends to shoot a CZ whenever i pay attention.
even on a 22LR (way cheaper than 9mm), some pistols fit fairly well and are cheap enough (Ruger, Buckmark), others fit well but have odd controls (High Standard), and others are wonderful but pricey (Smith model 41).
can you borrow pistols once you're at the range to figure out what kinda fit is good for you for 50+ rounds?