Existing law, added by Proposition 184, approved at the November 8, 1994, statewide general election, and amended by the Three Strikes Reform Act of 2012, approved as Proposition 36 at the November 6, 2012, statewide general election, commonly known as the Three Strikes Law, imposes additional years of imprisonment in state prison on a person who commits a serious or violent felony and has been convicted of, or who has a prior conviction for, a serious or violent felony. A prior juvenile adjudication constitutes a prior serious or violent felony conviction for purposes of this sentence enhancement if the juvenile was 16 years of age at the time and other requirements are met. The Legislature may directly amend these initiatives by a statute passed in each house by a 2 3 vote, or by a statute that becomes effective only when approved by the voters.