The first two were amazing but long ago, in sure there will be treats for those of us who remember them but I'm sure they'll be expecting a mostly fresh audience.
Just know if you hear 'go for the eyes boo' it's referencing a hamster.
I grew up with the first Baldur's Gate games and both are amazing but BG3 seems more of a standalone. I played the early access and I don't see much need to play the first 2, the story is not connected.
From what I've read, while there'll be a few nods and references you might only get if you've played the original games; the game can be played with no need to have played the originals.
Also, if you do decide to pick up the original two games, keep in mind they were made back in the THAC0 days.