Thank you for being hyped! I would recommend waiting. The expanded Steam version has some of the same story and characters as in the jam version, but we've reworked them a lot to fit in with the larger story, so the two versions of the game contradict each other in parts. Some parts are spoilers and others are totally different.
Of course we're happy to have people play both, but from my point of view, we're making the expanded version the best version of the game we can, so I want people to wait and enjoy that!