Is it a violation of the Sixth Amendment for the use of juvenile priors in a subsequent proceeding in adult court?

Hernandez argues that he should not have received a three strikes sentence in the first place because his prior serious felonies were juvenile offenses. He claims that the use ofjuvenile priors to enhance a sentence in a subsequent proceeding in adult court is a violation of the Sixth Amendment as interpreted in Apprendi v. New Jersey (2000) 530 U.S. 466 and its progeny because minors accused of criminal offenses in juvenile court have no right to trial by jury.