Utakata is a Jinchuuriki, and you need to pass the test to get that bio
which is quite difficult and i don't think you'll be able to pass it as you're only Chunnin no offense tho xD
Here is information about the Jinchuuriki. Just because you can't be Utakata doesn't mean you can never have it. What you can do know is train and build up to it.
You must be registered for see links
I would eventually like to have a Utakata or Yamato/Hashirama bio. But to get there I have to train in their respective areas and then when I get there I'll make it happen.