Call, call, raise the better line?

[Demana]

Live $3/6 game

Second hand at the table, so no reads.

Hero is CO with AKo

Preflop:
UTG folds, UTG1 calls, MP1 calls, MP2 folds, MP3 folds, Hero <font color="red">raises</font>, Button calls, SB folds, BB calls, UTG1 calls, MP1 calls.

Flop: KK5 (rainbow) (5 players)
Pot: (10.5 SB)

BB <font color="red">bets</font>, UTG1 folds, MP1 folds, Hero calls, Button calls.

Turn: 7 (completes rainbow) (3 players)
Pot: (7 BB)

BB bets, Hero happens to see Button get ready to muck so Hero then <font color="red">raises</font>, Button folds, BB folds

Is the better line to let the BB bluff till the river and then raise them? Once I saw the button ready to fold, I thought that I should try to get more from the BB.