Legal authority, yes. Actual authority to act in God's name, even with as limited as a deacon's priesthood is, no.
We got to remember, that this business of ordaining 12 or now 11 year olds is relatively new. Deacons used to be grown men in the New Testament. I am not 100 percent certain as to where the authorization came (no doubt the prophet and the 12) to ordain children to the priesthood of God, but it isnt without precedent. John the Baptist was ordained extremely young as well, so it's not that they cant be ordained earlier.
I think what turns people off to this true, albeit hard to swallow statement, is that most 12 year olds dont know anything at all. How could they have more authority than their mother or a sister missionary? But that's how it is. The priesthood of God is that big of a deal. Not seminary degrees from prestigious minister colleges, all the worldly experience, age, or financial standing make a bit of difference when it comes to having authority from God.
