How do I check when I created my guild? And when I started graal?  

You can't know when you started graal, profile>edit>guilds>manage guild  

ya when you click your name on your guild members list, your "date joined: " should be the same day you created the guild.

I only know the date i started graal because i remember valentine decorations in the windows of houses around graal and it was a few days after valentines. Maybe try looking at the first hats you own and use the holiday/event as a reference point.