She was facing the window, with Tara in between them. Screencap. There was a line of sight from the window to Tara. The only issue with that scene is the bullet 'bending' from an upwards angel from the ground to a fairly horizontal angel to hit Tara across the room. Still fairly implausible, but it didn't have to 'dodge' Willow.
You can see in that shot the hole in the window and the (bullet) hole in Tara are lined up horizontally.
But the bullet was fired upwards and there's nothing for it to ricochet off... Whatever way you look at it, that bullet should be in the ceiling somewhere between the window and Tara