have i put too much ram in my imac?

I have an imac i5 mid 2011 with 4 memory slots. It came stock with 4gb between 2 slots with 2 empty. I purchased 2x8gb corsair ram and installed them in the 2 remaining slots. I now have 20gb ram 1333MHz DDR3. I have now discovered a bunch of information saying the most I can have is 16. Can someone please tell me what the most I can have, should I take the 4 out,am i damaging my computer? Everything seems fine and it shows 20 gb in my mac info page. Thanks a lot!

I have the same exact machine as you do. While Apple states the maximum memory for that machine is 16 GB, the actual maximum is 32 GB as tested by Other World Computing and stated by Mactracker. You can add 12 more GB to your machine......