the mistake you made was to think that "ape" referred to only gorillas, it doesn't it's a branch that includes different types of apes, of which both humans and gorillas are a part of along with a few others such as organgutans, chimps etc...
no we actually do have a different chromosome count from great apes; when we split from our ancestors with chimps, one of our chromosomes is a combination of two chimp chromosomes or some shit idk google it