I went to DL a few years back, right before I turned 14. You will definitely be able to see everything in just a few days. I did like WDW better, but still had a good time at DL. There are some things in DL Park that they don't have in MK at WDW, such as the Alice in Wonderland ride (NOT the Teacups) and the Matterhorn. It's also interesting to notice the differences (differences being ones that only people who have been to either numerous times would recognize) such as the differences between the two Haunted Mansions or Splash Mountains. California Adventure is really cool, too, and has a lot of things not found in WDW. And I'm assuming you'll be there for the 50th anniversary, so that'll be cool to be in the original Magic Kingdom for that.