Is that diagram supposed to be cycle length? You know 28 days is just an average, right, we don’t all have a 28 day cycle. (Sadly, as mine is only around 23 days.) I also don’t understand where you think ovulation is happening, and I think it’s a one time event of the egg being released, not some ongoing thing (although that means you are fertile for a number of days before and after.) Ovulation happens about 14 days before the first day of mensuration regardless of cycle length.

For me I am horniest during my fertile period. But I’m always horny enough for sex any day, I just am extra horny that week. Since I have a short cycle my fertile time starts in the middle or end of my period.