They're never as exciting as those where we choose the leader of our country. But, you could be voting for someone who might choose to be the leader of our country later down the line.
In Texas we're voting for our Governor. The last Texas Governor went on to become president.
I voted early. Well on the last day of early voting, I was able to vote where ever. If you weren't a last-minute-procrastinating-early-voter like me and don't know where you're registered to vote, just ask Google "Where to Vote" and it'll help you out with a handy dandy little box for your address.
Course you gotta know you're registered. I'm sure Google can lead you to the right place to figure that out too.