Murph,
Seems like everyone has an opinion about your daughter's activities. You are lucky that she has an interest in spending time with you and that she is physically capable of doing operating this equipment. My son just turned 12. He has for a long time wanted to help out with the mowing. Unfortunately, he is very small for his age and his legs are not long enough to depress the clutch on my Craftsman garden tractor. Last summer, we bought a Snapper riding mower that fits him perfectly so now we share the mowing duties - he does the front and I do the back. Trying to teach him respect for all things motorized and responsibility of ownership. When I am satisfied that he can do an acceptable job on his own, he can take the next step and earn some money mowing for others.
Now, with the addition of the TC29D, we are back to square one. He really wants to operate it and I would love to teach him how, but he just can't quite get the clutch or the brakes fully depressed. This is delaying some quality time for us.
As far as the ATV goes, this is another interest I have but have not yet acted on it. I have no where to store 2 or more of these things (the "or more" is because I would love to make this a family activity). Just like the year I spent on TBN researching and learning about tractors before making a purchase, I have also logged many hours on a popular ATV forum (ATVNation.com). The issue of riding 2-up is always a hot topic and each side of the arguement seems to hold fast to their position. Personally, I'm inclined to favor the arguement of one rider per machine. On the other hand, for short rides on flat terrain, it kind of hard to believe anything bad would happen.
I don't subscribe to age guidlines that have been mandated. Some 12 year oldds are much to big for a 90 cc machine. Probable more dangerous for them than a larger bike. Certainly need to match the ATV with the rider's size and abilities, but not necessarily their age.
One thing I would question is the lack of a helmet in the picture. Certainly its hard to show off your pride and joy if she is wearing a helmet for the photo. However, I hope she (and you) always wear one while riding. Don't want to leave her brains on the trail.
You are a great dad. Many of us can learn from the example you are setting.