New behavior during colder temps

During this last week since it's been getting colder in our house my sons Beardie has been staying under his basking rock in his cave not being very active. He's almost a year old and we've had him since last april. Temps in the terrarium are 100-106 on his rock, 75-77 in his cave, and on the cool side 65 in the morning. Lights stay on from 7:30am-9pm. He has been eating and is awake during the day but seems less active and stays under his rock. Is this burmation? Should I switch how long his light stays on? Should I get a heat emitter and keep the temps up at night?

We have him in a 40 gallon tank with proper lighting. Substrate is a slate like porcelain tile. He eats a good mix of vegetables mostly collard greens, endive, and escarole. Occasional fruits like blueberry's. Eats crickets for a stable with vitamin/calcium mix every three days and occasionally super worms as a treat.

Any help is appreciated .
Thanks

This season in particular seems to have a lot of them slowing down. He's a bit young for brumation so I'd try to keep him up during the day and offer him food, time to roam around, etc. I'd keep the lights on the same schedule and temps at the same level (you may need to tweak the lights as the house gets cooler). If he's active and eating during the day he should be fine. If he wants to sleep in a little bit that's OK too =).

Contrary to the other post I'd advice you let him sleep if there are no other obvious health problems. I've had dragons as young as 10 months brumate. Is it common? No, but it does happen. The general rule of thumb with brumation is to let it happen if they're otherwise healthy. Just leave his light cycle (and temps) steady so that you don't stress his system. Offer food as you normally would for now and just stay diligent with your care moving forward. If it is in fact brumation he'll likely go down in a week or less. If he remains lethargic without actually going down then I would start exploring other potential causes.