They've probably got the age profile of the models in the pictures about right - in the middle of the median age range. For yourselves they look a bit young. For me they looked a bit old as I'm 36. Reading these forums helped me make a decision to book my first JY holiday (Wonder of China at Christmas).
I have no problem travelling alone as I've done it for 10+ years on truly alone holidays I've bespoke-built myself to western destinations. However now that I want to visit some of the more exotic destinations where I don't know the lay of the land and so a formal escorted tour is the only realistic way to go - I did not want to travel on a tour that is predominantly aimed at a senior age group either as there would be very little in common between us.
I'm at that awkward age that I can no longer put up with the clubbing and drinking culture, and immaturity associated with a sub-30-35 targeted holiday, but neither am I ready for a Saga holiday either. Maybe it's the male version of the 'change' kicking in. :-)
Oh, and I don't dance and have no interest in learning to dance so those discovery weekends were of no interest to me as they all mention that as an attraction, which to me is a disattraction.