I'm just relating our recent experience. The sign said 12 years and a certain height. We conversed with the marina/rental CM about the requirements and she knew how old my kids were and that they were planning on driving/riding the boat themselves. It was a-ok according to her. 
It is 16 to drive the boats alone...We get them every time we go..
My daughter just turned 16. She was very disappointed last year.
I'm really not trying to be contrary with you
For reference sake, the photo of the Mikala sign was taken last September.
Perhaps they changed the age limit? We were there 3 weeks ago and my DD13 and DS15 at the time (now 16) were wanting to rent them... the marina workers said, yep, they'd be good to go. They decided not to, they didn't want to spend their spending $ on them
I'm really not trying to be contrary with you
Carl, your information has to do with personal watercraft (wave runners), the water mice are different. Personal watercraft does require a driver's license even in MI.
If you look at the new thread and see the picture of the water mice rental, it is age 12 and 5' tall to rent. Our kids drove these water mice years ago when they were young--granted we rode along (and maybe there is a change now and the signage hasn't been changed), but they drove us and we switched when they got tired of making waves.
As with all things Disney--you get a different answer from every CM.
sorry guys.
I cannot believe we have not allowed our kids to drive the mice! And it goes soo slow with larger than normal me and a teen! I can send them out and say bye bye.. I know I asked last year and they said no. Fiddle faddle..
I get so indignant when I think I am right.
That's why I love the disboards, it's great discussion and really, there really is a lot of conflicting information out there, and sometimes we all get different information from different CMs. 
