Now when I got Skyrim with Dawnguard very soon(have played a little and had a lot of fun and can't wait to have it on me...), I was wondering if my doing Dawnguard at the same time will have the enemies way above me power wise...if so then shoud I wait for me to advance power wise so out the playing level is evened out more?

No, it totally scales to your character. I started a new character with Dawnguard. As soon as you hit level ten, the Dawnguard plot lines will open up. All the enemies in the Dawnguard quests are scaled to your current level just the same as the non-DLC quests. Have fun!

@bibamatt Thanks for the info

Oh... also take note once Dawnguard becomes active you will also be randomly ambushed by vampires constantly until you deal with the story line one way or the other.