"the supreme court ruled that juveniles must receive the same due process rights as an adult,such as the right to an attorney.The only right not guaranteed is the right to trial by jury". Is this following the 14 amendment?

14th? What about sixth amendment?

Not all adults are given the right to trial by jury either: minor offenses do not get that right.

The supreme court says what the sixth amendment means, in that view,yes it follows the 6th amendment...for now.