Do you know if you can vote?
Do you know where to go to vote?
If you are 18 years old and legal citizen of this country, then you can vote here.
(There are a few exceptions, like if you were convicted of a crime, but there are ways to regain your right to vote in many states.)
In order to vote, you must find out where to go to vote for your area. Places to find out this information would be: the local library, the local courthouse, your school or church will often know, and you can always visit this government web page and find your polling place.