Shouldn't I have already started?!

Kelsey • 21 years old and single
My first day of my last period was September  3rd. And I'm constantly having to click "late period" on my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a>. I had one irregular period in August but shouldn't I have already started by now?