Here is a simple trick to find out your Gmail account creation date.If you have deleted the first email sent by the Gmail team then there is another yet neglected method to find it If you have not changed your POP settings
Go to Settings –> Forwarding and POP/IMAP from your gmail account.
Now search for the line:
1. Status: POP is enabled for all mail that has arrived since YOUR DATE
You have your account creation date
This date is very important is security aspects! So don’t share it with anyone