100NL flopped set... what's the best line here?

[SunKing]

No real reads on villains, seemed like typical NL100 players.

PokerStars No-Limit Hold'em, $1.00 BB (6 handed) Poker-Stars Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($125.05)
UTG ($110.65)
MP ($100)
CO ($120.75)
Button ($104.30)
SB ($100)

Preflop: Hero is BB with 3, 3.
[color=#666666]2 folds</font>, [color=#CC3333]CO raises to $3</font>, Button calls $3, [color=#666666]1 fold</font>, Hero calls $2.

Flop: ($9.50) 3, 9, K [color=#0000FF](3 players)</font>
[color=#CC3333]Hero bets $5</font>, CO calls $5, Button calls $5.

Turn: ($24.50) 4 [color=#0000FF](3 players)</font>
Hero checks, [color=#CC3333]CO bets $10</font>, Button calls $10, [color=#CC3333]Hero raises to $31</font>, CO folds, Button folds.

Final Pot: $54.50

I was kind of mad at myself because I thought my line was way to obvious on the turn.. should I check raise the flop or bet the flop and again the turn if both called..? Thanks