People worry about this type of thing a lot more than the chickens do. For some reason many people post like chickens have to do certain things or they are not normal. Chickens are living animals, they don’t all do the same thing at the same age. They do not have to roost way up high to be happy and normal. Allow them to be children for a while.
Most of my brooder-raised chicks start to roost overnight on the high roosts somewhere between 10 to 12 weeks. I have had some brooder-raised chicks start to roost at five weeks. I’ve had some go a few months longer before they start to roost overnight. I’ve had a broody hen take her chicks to the roosts at two weeks. I’ve had some broody hens wean her chicks without ever taking them to the roosts. Usually when one moves to the roosts the others are not long to follow, but each brood is different.
When I transition my brooder raised chicks from the brooder to the grow-out coop, I leave them locked in the coop itself for about a week, then let them out to their own run, separated from the adults. Most of the time they sleep just below the door the first few nights instead of going back into the coop. I have to physically move them inside so I can lock the door for the night against predators. Sometimes they get the message to go inside after one night of doing that but usually some move inside and some continue to sleep beneath the door for a few days. I have to repeat putting them inside each night until they finally figure it out.
A couple of years ago I had about 20 that tried to sleep under the door the first night so I put them all inside. The next night I was down there just about the time they were getting ready to sleep doing something else and they were piling in front of the door again, but when they saw me they all went inside. I never had any problems with them trying to sleep outside again. It was hilarious to watch them. They looked like kids caught doing something wrong.
Eventually your chicks will transition all the way to the roosts. That may be in a few days, that may be in a couple of months. If you feel you have to micromanage their life you can start moving them to the roosts at night. They will probably start roosting up their sooner but I allow mine to go to the roosts when they are ready. People care about this stuff a lot more than the chickens do.