40’s & want get pregnant…

Hello. I just turn 40 years old and I will like to have my second baby, we stop care about the ovulation days that the app said, and let the seed go. Well last month I supposed to have my period on 23rd , and I really started been anxious but it was come late by 3 days., was kind of regular period, same quantity of days and color, wired symptoms, was like I have all symptoms in different days.( I mean one month I have sore nipples, back pain, abdominal pain, so I got all of them to receive this period) the only different was a dizziness twice one of those days. My question is why if I am following the fertility days, what I don’t get pregnant at the first time? Maybe it’s because my age!!! May my body react like, what is that (sperm) and just lose the control on my period clock!! I have a lot of doubts. Can someone help my to figure out! Or I just getting frustrate!!!