If its bubbling most likely its not done so the gravity sample would be kind of a waste. I'd wait till it stops bubbling at least. Also, a lot of brewing recipes have days/weeks scheduled. Ignore them, they are ballpark only, and probably only represent what the recipe writer usually sees. Yeast cant read calendars and rarely follow the same schedule every time. I look for lack of airlock activity, then lack of activity in the fermenter. If theres no bubbles and it looks like the yeast are settling out of solution, its getting towards done.