Adjustment period for new mice?

Hello it's been 24 hours since I brought my mouse home. He's 3-4 weeks old though I would have preferred one a bit older.

Since he arrived he's been eating and drinking good and likes the treats I gave him. He also seems to really like the movement of the wheel though hasn't figured out how to use it 'properly' yet.

He's also been making use of the hideouts and really seems to like the hay to nest in. However he hasn't been big on exploring the whole space of the cage or climbing on the clutter. Maybe because he's still too young? And of course he does alternate with sleeping/hiding in his hideouts a lot of the time.