I say go for it. On the conditions that they can comfortably reach pegs and grab rail. Did a few thousand miles with my son on the back covering middle England and Ireland. I have done the car park thing but he wanted more. So a deal was made. He had all the protective gear before he went on the bike. I purchased a set of "love handles" a webbing belt with two handles the pillion can hold onto as well to give him a bit more security should he need it. I also taught him how to sit as a pillion and worked out a few signals. He loved it at the age of 16 bought his own bike and got his liscense. https://www.amazon.co.uk/Ryde-Motor...coding=UTF8&psc=1&refRID=YPW8BR4GPYKS74K75NMN