LOL. That’s what one side’s lawyer says. The other one says the operator was negligent for failing to verify age or enforce stated limits.
Age is a pretty arbitrary way to eliminate or control risk. If the excursion was in the US, I would expect a long list of warnings and/or exclusions; under 5, over 75, under 350 lbs, no pregnant women, no pacemakers, no wheelchairs, etc.