I’m 20 years old and might be pregnant with baby number two.

So the thing is the past year the time in between periods has ranged from 15-20 days and my period ranging around 6 days. However my tracker on this app was set to every 30 days in between periods. I just changed it for accuracy but the app itself hasn’t changed yet. On the app it says I’m a week late tomorrow, but by my average I should be almost two weeks late. Should I go by what the app says?