[Spoilers] Question about a certain point in Blood and Wine main quest line

Just a quick question - no spoilers please.

I just got to the quest Capture the Castle and when I approached the area, the game said it was a point of no return and that I should save.

I'm just wondering how close I am to finishing the main story for B&W in terms of hours left therein. Is like like the 2/3 mark?

Thanks!

EDIT: Thanks all for the replies, good to know where I'm at!