What day did would be the first positive opk?

Katie • TTC since June 2013•Endometriosis and Infertility•

Would you consider CD 16 or 17 as my first positive opk?

Also has anyone else had this many positive opk for this many days? Today I have had mild cramps on and off for 5 minutes intervals. Could this be a sign of ovulation happening today or does that Mean it will happen tomorrow?

We BD on CD 16 and every other day after that. Should we BD again tonight just to be sure?