That might be the perfect Dad to have in a situation like this, actually. (Unless you think he'll go fight the guy or pull you out of the church when you like going). At least he'll take it seriously and as an important thing, better that than having a parent who thinks you are imagining it. I'll go with telling your Dad. You can only do so much. You're 14 and you've tried... this is what parents are for. I doubt they'd like what this guy did.