What difference does it make if we vote?
17 million voted for leaving the EU
Voting means bugger all. I'm not voting
You do know that the UK has a population of virtually 67 million people ? (obviously some are children and a few, for other reasons, not eligible to vote).
Do the maths.
The country is leaving the EU which is a MASSIVE constitutional, legal, political, trade and social shift that will have impact for years to come, when ONLY 17million voted for it.
How can you possibly say that "voting means bugger all" ? 
If everyone who didn't vote in the referendum had voted, the result could still have been a fairly even split, or it might have been an overwhelming vote to leave or it might have been an overwhelming vote to remain. We don't know, but it would at least be a decision taken by everyone it is affecting, not a decision taken by so few people.