2-4 NL AQ without position

[pofi]

I know nothing about villian. I just started session.
Preflop: I am MP1 with Ac, Qd.
3 folds. I raise 12. MP2 calls.Rest of the field fold

Flop(30): 5d, Tc, 2d
I bet 20. MP2 calls

Turn(70): As
I check.MP2 bet 50. I call.

River(170): Ad
I check, MP2 checks.

What can you say about playing AQ in such way? Did I really must bet river about 1/3 pot or something?Any thoughts?