Dirt bike for my 7 year old?

[b44]

I got my son a thumpstar tsb110cc, was just a tad tall for him when he1st started riding but now he's 8 and is perfect size, also fitted atv type gear shifter so he can easily change up and down, he jumps on my daughters 50cc crf clone and is way too big for it, it's that difficult age where they are inbetween, he only goes to 3rd gear, more than enough power, he rides within his ability, he's wary of the power, he only weighs 28kg so that little 110cc Flys