@Roeland
Interesting. My start date was October 31st 2016. Right around when I thought I started.
@MadameCurie
On our iPhones you just go to the App Store and click, in the upper right hand corner, on the account icon, then you click on purchased, and then you scroll around until you find the date you downloaded the app. That is your start date.
I do not know how it works on Androids.