There aren't nearly enough options available in or near Ottawa to try off-road riding for kids or for adults. I'll ask BMA to set up a sub-forum on here specifically to connect those with kids or beginner bikes in their possession with those wanting their kids to try out the sport. Try-out-a-kids-bike rides board? There are risks of course such as who pays for damages to the bikes and are the bikes in good enough condition to safely let someone try. It should be in everyone's interest here to try to help facilitate the next generation of off-road riders.
I have no kid bikes in the size you are looking for but I do have a CRF150F that is good for a person about 5 feet tall to ride. Say, 13 years old and up. (I ride it
). It and my CRF230F are always available to try and I have a 2.5 km kid friendly trail network and a largish lawn that people could bring kid bikes to and meet those rider wanting to try riding. I don't coordinate these meetings, that's up to you. This could also be a try before you buy situation where you could try a bike but also buy a bike if owner is interested in selling it.
I had 14 scheduled ride-days last year mostly on Saturdays and will continue to host these events in 2018. All ride days are announced here on this forum about 1-2 weeks in advance. I may be able to help with teaching a bit but I will not babysit your kid, (I like to ride and visit on these ride-days). Bike owners and borrowers are most welcome to meet here on a ride day or possibly other times as can be arranged with me. I won't accept any fee for use of my trails but donations of riding gear, especially in kids sizes will be accepted and the gear will be made available for all to borrow as needed, and time spent doing trail maintenance is always appreciated.
Sorry to have hijacked your thread.