1/3 - Call or fold to river bet?

1/3 game at a charity event. The villain is a 19 or 20 year old kid, kind of preppy. I'd only been playing with him for about twenty minutes. He just reloaded for $200 after getting stacked for about the same amount on a flip (QQ < AK).

Hero is in the CO with 44

Folds to HJ who raises to 10, hero calls, villain (BTN) calls, blinds fold

Flop 356 with one diamond, checks around (probably should have bet here but whatever)

Turn Ad

Checks to villain who bets 20, HJ folds, hero calls

River 6d

Hero checks, villain bets 60, hero?