A6s raises pre-flop

[checkmate36]

PokerStars 0.10/0.20 Hold'em (10 handed) FTR converter on zerodivide.cx

All folded to me pre-flop and I knew I was going to play so I open raised this hand. The CO (rated as taz with 64/20 stats) had been calling my pre-flop raises all session with junk. [img]/images/graemlins/grin.gif[/img]

Preflop: Hero is MP2 with A[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">4 folds</font>, <font color="#CC3333">Hero raises</font>, <font color="#666666">1 fold</font>, CO calls, <font color="#666666">3 folds</font>.

Flop: (5.50 SB) J[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">CO bets</font>, <font color="#CC3333">Hero raises</font>, CO calls.

Turn: (4.75 BB) 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

River: (6.75 BB) 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

Final Pot: 8.75 BB

I was going to limp this hand pre-flop but thought raising was the play. My hand was probably best so I hit it. Anyone limp with this one? Thanks for any thoughts.