Questions before treatment

Birth control pills to trigger the cycle before taking letrozole

Hi, I (30Y) stopped taking the pill 11 months ago. I have had 3-4 periods (irregular); the last one in August this year. According to my gynecologist, my blood work/hormone levels are in the normal range. Currently no active ovaries visible and only moderate mucosal development. I am now supposed to take letrozole 5 days into my cycle to get pregnant. Since my period is not starting, I am now supposed to first go back on the pill to trigger my period for 21 days and then start Letrozole. Is that usual?