At present I am teaching multiple people of all ages nearly every day - at Castell Henlys and at Top of the Woods campsite - and have only had a few that needed me to "guide their hands" (ie hold their hands and do the strikes for them) mainly young children with poor manual dexterity.
Having said that, this summer I have had 3 five-year-olds succeed without help.
All used the charcloth on top of the flint method, though I also demonstrate the "down strike" method. I even reverse grip and down strike to shower my arm with sparks to show they do not hurt!
I do not get paid at Castell Henlys but get through masses of flint and char cloth, not to mention hay for tinder bundles!
The look on folks faces when they make fire is worth it!