You really should register to vote if you're not currently on the electoral register. It's easy and takes only a couple of minutes.
You've only got until 22nd May to do this if you want to be a part of the 2017 general election.
And you do want to be a part of it, don't you? These things are important. Anyway, go here to register: https://www.gov.uk/register-to-vote
And if you're stuck as to why you should bother, here's a few reasons for ya: http://votingcounts.org.uk/why-should-you-vote-html