Cycle buddies

Does anyone have the same or similar chart and haven’t gotten their period yet? I used to have irregular periods but no longer do due to dramatic weight loss. Since then my periods have become regular and normally come between the 17th and 19th of every month. The app predicted that my cycle would start on the 20th this month which I found a little odd being that it hasn’t since last year (Oct). But now the 20th is here and no period and I’m terrified to take a test. How long should I wait to take one ? Baby Dust to all TTC 🤞🏼💞🙏🏼🥰