So if you don't know, what size bike do I need, here are the answers: I am cm tall, what would be my correct bike size? . (brand new, not used) online but the Specs does not say its frame (or wheel) size just that's general adult.
What you will see in these charts is that adult bikes are generally measured by their bicycle frame size. Wheel size is a very important metric if you are a child.
Growing up, bike sizing was a luxury we couldn't afford. time, they would make the frames taller but would keep the top tube the same length.