
Welcome to the forum, glad you joined.
Looks like you have plenty of height to work with, That is good. And it looks like you've done well on the coop.
The way I determine height is to determine the height of the coop floor, including bedding. The pop door and human door need to be high enough that the bedding doesn't fall out and you can open them.
Then I determine the height of the nests. Some people put a milk crate or something like that on the coop floor as a nest. Some put them up higher. If you have a bad back you might not want to bend over to gather eggs. I let my broody hens hatch in my nests 3 or 4 feet off the coop floor but some people would be concerned about that.
Then I put the roost noticeably higher than the nests or anything else I don't want them sleeping in or on. There are always exceptions but most chickens prefer to sleep as high as they can get. But keep the roosts as low as you reasonably can. Your coop looks like it is plenty big enough so you won't have this issue but the higher the roost the more clear room the chickens need to fly down. Try to not block their landing area with feeders or waterers.
Then I put my winter ventilation well above the chickens when they are on the roost. In Pennsylvania you will need ventilation in the winter but you don't want a cold breeze to hit them. Your coop front is open but it looks like it is inside a building. If you want to talk ventilation we can.
If you have what I call "special needs" chickens, like Silkies that can't fly or one that is somehow handicapped, you may need to make special accommodations. As Sylvie said they can often do pretty well on their own but in some cases ramps or steps may help. So be a bit flexible there. But my full sized fowl have no problems flying up and down to my 4' high nests or 5' high roosts. Just make sure they have room to spread their wings and fly.
To me it is more important to pick a nest height that is comfortable to you than over-worrying about what the chickens will think. You have the room to do what you want. Another reason more room is better.