50nl - ak in small 3bet pot

[danny8]

Cryptologic - No Limit Hold'em Cash Game - $0.25/$0.50 Blinds - 5 Players - (LegoPoker Hand History Converter)

Hero (SB): $50.25
BB: $46.77
UTG: $33.30
CO: $82.85
BTN: $16.86

Reads: <font color="blue">villain was 46/19/2.25 ~20hands. standard loose agro guy</font>

Preflop: Hero is dealt A[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/spade.gif[/img] (5 Players)
<font color="red">UTG raises to $1.00</font>, 2 folds, <font color="red">Hero raises to $4.00</font>, BB calls $3.50, UTG folds

Flop: ($8.5) 9[img]/images/graemlins/diamond.gif[/img] 8[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">Hero bets $6.50</font>, BB calls $6.50

Turn: ($22) 3[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">Hero bets $15.00</font>, <font color="red">BB raises all-in to $36.27</font>, Hero calls $21.27


how do you play the turn here and why? since i had the nfd i decided i was gonna go with it, figured he may well check behind with a weaker K, and if a [img]/images/graemlins/spade.gif[/img] comes on the river and he doesnt have 1 im not getting paid. So decided to b/c

all comments appreciated, thanks!