this is really interesting. if you are questioning your chapter lengths, i wonder if it's because YOU think they should be shorter or longer.
i say this because, as i prepare to dive into my first revision, i know one of the first things i plan to do is break down all my chapters into shorter chaps. there's nothing wrong with my 4-5k word chapters, as a rule, but reading over my work, i can see cliff hangers and potential breaks about midway through each chapter.
i also write YA and want to increase the pace.
so while it may not matter to an agent or editor at face value, i can see -for my own story- that changing the chapter lengths will actually improve the feel and flow of the read.
in short, i'm saying it's a question only you can answer, because you know your work best. but based on the awesome advice already on here, it certainly seems you don't have to change 'em if you don't want to.
