Yes. If you're able to stand (not charged first) as your first part of your move you may then either shoot (you've only done a 1/2 move) or charge (at half distance). If you are tagged before you stand then you have to fight from that position with the penalties involved.
This is the reason the Natures Wrath spell in SBG can be so good if you get the timing right. Even just one turn of charging your forces against a good sized group of knocked down models can determine the game. Likewise it's a reason Expert Riders have an extra little advantage, though I'd prefer not to loose my mount in the first place.
