Here's what he said in the video:
In context, the crack about the priest was to underscore a serious point he was making, that in his opinion, "13 years old and sexually mature" is OK and society needs to be less uptight about it. For any pedo-adjacent comments to be a joke, he'd have to have been performing entirely ironically throughout his appearance on the Drunken Peasants, much like that "Mr. Girl" character claims to be.
What you're talking about is probably his response to the backlash, where he said he was 17 during his relationship with the priest (above the UK AOC of 16) - which, whether true or not, or if "Father Michael" was invented entirely for a gag about pedo priests - doesn't address the general comment he made about 13 year olds.