So when I was watching ed, edd, and eddy on netflix I got to the episode "A pinch to grow an Ed" when Edd walks to they wall where he is measuring himself the other lines say start at the age of 5 and go up til he is 11 and he adds a new line to the walk. This line represents that he is the age of 12 so that makes Eddy the age of twelve and since all him Ed and Double- D are in the same grade that makes them the age of 12 years old as well. By the time the season is close to being over if they continued the series they would have been 13 years old that next summer. So I have found the answer to my question that I proposed a while back of how old are the Eds in the first place. Which this explains the reason for Eddies obsestion with trying to be Mr.Moocho man and how the eds, and kevin all have feelings for Nazz. Also the Kanker Sisters are also the same age because when the eds go back to school they try to switch home rooms with them. Nazz, The Eds, and The Kankers, Rolf, and Johny are all the same age and going through the pre-teen hormonal change stage. This also would put them all in the 7th or 8th grade. Sarah and Jimmy are possibly in the 6th grade because they also attend the same school as the Eds, when the school year starts. This is all concluded from my resent observation of watching the show.
So to conclude, The Eds are 12 years of age. If anyone has something else to add to my resent discovery feel free to comment and add on.