To register to vote, you must meet these qualifications:

• You must be a United States citizen
• You must be at least 18 years old on or before the next election (OR for a General Primary, you must be at least 17 and will be 18 by the General Election)
• You must live in your election precinct at least 30 days before the next election
• You must not be convicted and in jail
• You cannot claim the right to vote anywhere else

Source: Register to Vote page.