Yes, Sylvia, I agree that each would have been too young to be married.
There are some other candidates for each as I suggested before.

There are a couple of older Ann Killips in Lonan
Ann ch 08 MAY 1791 Lonan d/o John Killip
Ann ch : 20 APR 1788 Lonan d/o John Killip

There is another Onchan Thomas Cain(e)
Thomas ch 09 JAN 1791 Onchan s/o Thomas Cain(e)

I don't know anything about the Thomas Caine of 1791 or the one of 1795.

Hopefully, the marriage record or some other documents will give some clues on each of them.

Donna