Unfortunately it's always a risk taking the seats just behind the curtain as the curtain can, and often is, moved backwards. It's been fairly well documented here.

That said, guess who's just picked seat 4A behind the curtain on a flight this week?! Stupid thing is I suspect the CE cabin WILL actually move back due to the flight loads. See even we staff can be dumb with our seat assignments!

(Oh, and I'm not calling the OP dumb, just myself )