I think the typical age depended somewhat on the year and the Bishop (eg not sure how many Wilson did in his old age mid 18th, the bishops post Hildesley were not that good) - I've not looked at mid to late 19th century (for whom the records often give age) but 18th C - servants were supposed to be sent to confirmation class by their master, sometimes you see siblings in the same class so there must have been some variation in age, I've also seen a few married women in the list