Yes, I think I'll turn down that commission.

But I did take a look at the story of Joseph (the son of Jacob) to make sure I remembered it correctly. He was probably a teenager when he was sold into slavery by his brothers, and he had been in Potiphar's household long enough that Potiphar had placed him in charge of the whole household before Potiphar's wife tried to seduce Joseph. While we don't have exact ages, most commentators believe Joseph was in his twenties when the incident happened. Potiphar's wife may have been significantly older than Joseph, but that does not play any role in the story.

However, based on clues in the text many commentators believe that Joseph may have married Potiphar's daughter when Joseph was in his thirties - so there is the possibility of pedophilia there - we do not learn her age, but girls often got married young in that era.

Still, the only acts commented on with disapproval were the attempt at adultery and the false accusation on the part of Potiphar's wife. There is no condemnation (or even a mention) of a difference in age.

Any attempt to tie the story to pedophilia is an artifact of contemporary (in)sensibilities that consider adultery harmless and pedophilia as criminal, as the issue of pedophilia is entirely absent from the original.