NL20 SH QJs

Hey,
been busy for a while.

His 3b against SB is 27 but not big sample.

You ask the right question!

To be honest I got scared of the ace.
Don't have well defined calling range for this situation (preflop).
But don't think I got much aces ( ATs-Aqs and maybe AJ, AQo) and on the other hand he probably got all of them.

Guess river bet should be 3/4 of the pot?

Thanks

Although you don't have many Ax and he has some, if you don't bluff him off K high, 76 type hands on the river, how can you make the flop call profitable? That's the main problem! Once you float that flop in 3bet pot OOP you have to bluff river quite often. You already call preflop assuming his range is far from premium to begin with.

That's the only thing I would definitely change about your line, river play. Apart from that, pre can be OK, flop is marginal but is OK when people give up on turns a lot and you take it down on the river. What you did is call flop with the plan of taking it down later, apart from the taking it down later part which makes it bad now.