But there are other reasons to vote and your vote counts in ways you never thought of. The government doesn't know who you voted for, but they do know whether or not you voted. They track information for statistical purposes to determine how many young people are voting as compared to other age groups. That way politicians know what age groups to target in order to win elections. The fact that you even voted adds one vote to the number of young people who participated.
Old people are the most reliable voters.
They have the highest percentage of voters of any age group. And because of that, old people get what they want. If you're running for public office, you better be protecting the interests of old people because old people will vote you out. On the other hand, young people don't vote in large numbers and it's not worth a politicians time to put a lot of effort in courting the young vote. Not that youth isn't important, but if politician A focuses on the young voters and politician B focuses on the old voters, politician B wins, because old people turn out.