I used to work out 9 days safe 10 days not 9 days safe - so my way you are looking at the 10 days
But don't stress these things happen when they happen
relax theres no hurry you are young !
Since every once in a wile you might have a "bump" in your cycle (early or late), you should track a few cycles then average out the days. This will give you a broad idea as to when you might be ovulating to time bding better. You can also use the ovulation kits each month to find out when you ovulate or if you really want to cover all your basis...bd on the 8th, 10th, 12th, 14th, 16th and 18th days of each cycle. That should cover any early or late ovulations. Good luck. :)