$5NL: Flopped a set, is this a fold on the flop?

[Sean Fraley]

This was about my fourth or fifth hand at the table, so no reads. I didn't reraise the minraise from CO, since at $5NL, this could mean AA as much as anything else.

Poker Stars
No Limit Holdem Ring game
Blinds: $0.01/$0.02
6 players
Converter

Stack sizes:
UTG: $7.87
UTG+1: $3.86
CO: $1.33
Button: $4.12
Hero: $5.18
BB: $2.57

Pre-flop: (6 players) Hero is SB with 5[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/spade.gif[/img]
UTG calls, UTG+1 calls, <font color="#cc0000">CO raises to $0.04</font>, Button folds, Hero calls, BB calls, UTG calls, UTG+1 calls.

Flop: 7[img]/images/graemlins/spade.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] ($0.2, 5 players)
<font color="#cc0000">Hero bets $0.21</font>, BB calls, <font color="#cc0000">UTG raises to $5.22</font>, 2 folds, Hero ???