Should I suspect I'm ahead on the flop here?

[UncleDuke]

Hi folks, I'm relatively new to NL hold em. Here's a hand I played today where I laid down my hand to a bet on the flop, and I'd appreciate some advice as to whether it was the smart play or not.

This is on a Cryptologic $.5/$1 ($100 max buy-in) NLHE table. I don't think their hand histories fit with the converter, but the cut and paste is pretty good.

Table "Stockton" Seat 9 is the button.
Seat 1: SB ($114 in chips)
Seat 2: BB ($132.75 in chips)
Seat 3: UTG ($98 in chips)
Seat 4: UTG+1 ($171.75 in chips)
Seat 5: UTG+2 ($100 in chips)
Seat 7: MP1 ($97.75 in chips)
Seat 8: CO ($60.50 in chips)
Seat 9: Hero (button) ($113.25 in chips)
SB: posts small blind $0.50
BB: posts big blind $1
----- HOLE CARDS -----
dealt to Hero [Qd Qh]
UTG: calls $1
UTG+1: calls $1
UTG+2: calls $1
MP1: raises $3
CO: folds
Hero: raises $8
SB: folds
BB: calls $7
UTG: folds
UTG+1: folds
UTG+2: folds
MP1: calls $5
----- FLOP ----- [2s Ah 5s]
BB: checks
MP1: bets $12
Hero: folds
BB: calls $12
----- TURN ----- [2s Ah 5s][9h]
BB: checks
MP1: bets $10
BB: calls $10
----- RIVER ----- [2s Ah 5s 9h][9c]
BB: checks
MP1: checks
----- SHOW DOWN -----
BB: shows [3s 3c] (Two Pairs, Nines and Threes, Ace high)
MP1: shows [6c 6d] (Two Pairs, Nines and Sixes, Ace high)
MP1 collected $68.50 from Main pot

I had only been at the table for a few hands and didn't have a read on either of the relevant players. My thinking was that with MP1 raising initially, both of them calling my reraise, and then MP1 betting into me on the flop, an ace was probably out there. On the other hand, his flop bet was fairly small compared to the pot. I suppose MP1 could be taking a shot at the pot on theory that I have a big pair other than aces, which was the case. I have no clue what BB was doing, but if he does it often, I hope to play against him again. [img]/images/graemlins/grin.gif[/img]

Anyway, was this a weak-tight laydown, or will someone show me an ace most of the time if I stay with my queens here?