It doesn't make sense to pre-order now, since the game is still over three months away. Prices on Steam will be the same, no matter what (until launch).

People always say not to pre-order, but I think it's fine shortly before release, especially after reviews are out and/or you will play the game anyway. That way you get any potential bonuses or can maybe pre-load the game. Buying on Steam or GOG directly also lets you refund the game, so there is little to no risk.