I can't think of any reason this would be any weirder to Ariel than being a human would be. Someone who didn't think about it very hard might think it'd be less weird, but those people are looking at it from a human perspective that doesn't really apply.
They should make a Disney movie about centaurs. They already did humans, animals, gods, anthropomorphic animals, ogres, fairies, mermaids, robots, aliens, toys, why not centaurs? Fantasia doesn't count.