Should I close my recent credit card?

I was approve for a JCpenny credit card. I found out that it was a mistake and I don't really see any advantage from it.
I care for my credit history, and I have 2 other cards from banks with a limit of $8500 and I utilize only 5% of them each month and pay them off. So, utilization ratio won't be a problem if I closed the JCpenny specially its limit is only $700. The reason I want to close it, is because it is very recent one, and according to credit karma (I know CK is just an estimated) it was that card which pulled down my (Avg years I have a credit history). Will closing it will increase the (Avg years I have a credit history) then?

?2014-12-30T21:39:20Z

For your peace of mind, close it. The small temporary ding (if any) to your credit report will go away.

{I have not used my JCP card in a month of Sundays, but I guess it is still valid, but you are right, it is not worth anything. No mailings, no special discounts,,,, .}

P S Feel free to utilize your cards more - as long as you always pay in full.