Is it time to raise the voting age?

I don't believe that 18, 19, and 20 yr olds have the life experience that allows them to make an informed decision with regards to picking a candidate. Most have never paid income tax or have investments. My 18 year old Stepson is voting for Obama in 2012 because he thinks it will be cool to have a black president. His mom encourages him to support Obama. Is it time to raise the voting age to 21?