Not really sure what I did wrong here...

1st hand. No priors:

Full Tilt Poker $0.25/$0.50 No Limit Hold'em - 8 players - http://www.thehandconverter.com/hands/356916
The Official DeucesCracked.com Hand History Converter

MP1: $9.75
MP2: $65.70
CO: $27.55
BTN: $39.35
SB: $50.00
Hero (BB): $50.00
UTG: $10.00
UTG+1: $18.70

Pre Flop: ($0.75) Hero is BB with As Ah
1 fold, UTG+1 calls $0.50, 1 fold, MP2 raises to $1, 3 folds, Hero raises to $4, UTG+1 calls $3.50, MP2 calls $3

Flop: ($12.25) 6s Jh 8s (3 players)
Hero bets $6, UTG+1 folds, MP2 calls $6

Turn: ($24.25) 5h (2 players)
Hero bets $15, MP2 calls $15

River: ($54.25) Qc (2 players)
Hero bets $25 all in, MP2 calls $25
I'm committed here, right? I don't want to give him the opportunity to check through. Should I have just shoved the turn?

Final Pot: $104.25
MP2 shows Th 9d (a straight, Queen high)
Hero shows As Ah (a pair of Aces)
MP2 wins $101.25
(Rake: $3.00)