United States v. Ceja-Prado, 333 F.3d 1046 (9th Cir. June 25, 2003) (where proof of defendant's age is lacking, and s/he may have been a juvenile at the time the crime was committed, there may be no federal
jurisdiction over defendant's case pursuant to the Federal Juvenile Delinquency Act, 18 U.S.C. § 5031).