Hi Markos, welcome to the forum!
I agree with the others...with only 3 cc's reporting, closing one card will hurt you.
Work on getting the utilization down below 10%, and let those low balances start reporting. Pull your FICO scores and see where you stand.
You should get a substantial score rise when you pay the balances down. Right now they are hurting you.
When your FICO scores are high enough for you, apply for 1 or 2 more cc's. If approved, THEN close the card...but of course with a $0 balance!
What are your FICO scores? Now would be a good time to pull all 3 reports as there is a 25% discount for the month of April.
I'm pulling mine toward the end of the month, after all my ccc's have updated to the CA's.