What Causes Delayed Periods After Stopping Birth Control While UPT Is Negative?

I am a 44 year female who was always very consistent with my periods, I stopped birth control pills about 8 mts ago as we were given it a try to get pregnant again but we were not able to, I stopped having my period in March, FEbruary was my last regular period and have taken pregnancy tests which were negative, wondering if is normal that my period stopped completely at once