One of the benefits of the Billings Ovulation Method™ is that your chart doesn't need to be the same month after month. You just take one day at a time, deciding each day if what you've charted indicates infertility or possible fertility. Then you apply the guidelines, depending on whether you want to achieve or avoid pregnancy.
If you've stopped hormonal contraception you may not show signs of fertility for some weeks or months until your own hormones return to normal function. You may have regular bleeds but not observe the normal mucus changes indicating fertility. You may have long, irregular cycles with patches of mucus, but no recognisable Peak. These are signs that you haven't yet started ovulating again, or that your cervix hasn't recovered from the effect of the contraceptive and isn’t yet producing mucus which will support sperm. Your Billings Ovulation Method™ tutor will help you work out what is happening. If you've stopped contraception but still want to avoid pregnancy, it's simply a matter of charting accurately and correctly applying the Rules of the Billings Ovulation Method™.
From about the age of fifty most women are infertile. The change from fertility to infertility is usually gradual, occurring over a number of years. During this time menstrual cycles often become extremely variable in length and mucus episodes less frequent.