You should think through your betsizing and how to set up a smooth river shove. I'd bet something like 2.50 - 6.50 - all in (~14).

I would also gladly 4b/call preflop, 18 hands is nothing, the only thing you know is that he most likely isn't a mad loose fish. He can be anything from a 4/4 running hot or 32/24 running carddead.