[I am fish]

You should 3Bet preflop because...

Your opponent is more likely to be on a steal, thus he is more likely to be raising with a broader range of hands.

You want the Blinds to fold.

You take the initiative and control of the hand which is good. You have position on the CO for the rest of the hand. If blanks fall on the flop, and your opponent checks to you, then you can steal the pot with a bet a lot of times.

Given the way you played it, I would be inclined to just call the 3Bet on the flop and go into call down mode.

The thing is that it is a fairly uncoridinated flop, so your opponent is more likely to have a hand when he 3 bets since there isn't anything really that he would semibluff with.

I think calling down then is right move. If he has a hand like TT, JJ, QQ, KK, AT or lower... you can let him bet into you with the worse hand. At the same time, if you are beat, then you don't lose as much.