If he says anything else, I would tell him that you feel uncomfortable around teenage girls. They giggle too much... or usually that age girl can't keep their hands off of you... or flirt too much.
Then I would look him in the eye, and say, "I'de rather spend some quality time with you. Maybe we could go fishing after service next Saturday." Make sure there is 2 witnesses there. Winking at him is optional. HL