I went for FP at least a month prior to my scheduled date. When I went to the St. Paul center, I found that two or three people were there. The lady there told me that fortunately only 10 people were scheduled for FP that day and 150 the next day. So, if I had gone there the next day, they would have returned me. So, I think it depends on how many people are scheduled in a given day. If 10-20 people are scheduled in a day, then the center might allow early FP. But call ahead and see whether you can find a slow day. In any case, it all depends on the center