It's a safe guess that this game won't be released until late 20 since development has only started in summer 17 and even 3 years isn't a lot for an RPG. So I wouldn't be surprised if Baldurs Gate 3 is a 2021 title. I am pretty much convinced they have only announced it this year because of the Stadia which launches in November.
Though DOS 2's early access started one year before launch so there is a very small chance we will be able to play this winter or next spring.
