The T-Hawk is basically the same as the Challenger control-wise. Tail configuration is different, but the end result is the same.

I would be surprised if a 12-year-old CAN'T control the Commander. Remember, video games + youth = hand-eye coordination...

When you launch for the first time, the plane probably won't fly straight ahead in a moderate climb. If it does, consider yourself lucky.

When the plane goes left or right after launch, don't try to fight it. Back off on the power and land before it gets too high, then adjust the tail to compensate. There are little knobs on the control horns back there. If the plane turns left, adjust the left tail flap up a little and the right tail flap down a little. Do the reverse to correct for a right turn.

The plane may also try to climb too steeply. Try and adjust that with the adjuster screws under the tail. You may need to shim, but probably not.

Get the plane so it flies straight ahead, and doesn't climb or dive under power, before you ever try to make a turn or gain much altitude.