Interesting interactive poll here in The Economist - showing how close it is.
So, if you're old, conservative, poorly educated, you're more likely to favour brexit. No surprise there.
Not much difference in polling for women/men, slightly more in favour of brexit from North of England - Scotland firmly in favour of staying.
Old or conservative or poorly educated rather than all three.
It bears out my earlier point that those not old enough to recall Britain being an independent country favour staying in, largely I am sure because the alternative is an unknown quantity for them, having never known anything but diktats from their Euro Commissars.