Age differences and 'granny sex'
There is a 21 year age difference between the actress who plays Tillie (Fionnula Flanagan) and Jim Carrey. There is an 18 year age difference between Jim Carrey and Zooey Deschanel.
If one is acceptable then so is the other. Tillie has as much of a right to have sex and the age gap, though uncomfortably large, is irrelevant if the people involved enjoy the relationship. Old people can be sexy!