Confused

Christy • Been with my boyfriend for 13 years now we really havent never used protection other than a depo shot for about a year and i stopped and just havent ever got pregna

Ok can someone explain to me why the 17th says ovulating but yet it's only 19.2 and its supposed to be your good day or what I took it as my best days are the 15-16 cause it's the highest percentage ..