Worth mentioning the current non-EU nations have valid reasons for their success (norway - oil, switzerland - the worlds dodgy bank.. etc).
It's a shame the EU hasn't been a greater success really - we should definitely be pushing towards global union in some form - but the execution of the EU masterplan has been weak and counter productive in lots of places. For me a vote to stay seems to be a vote for the status quo, and that's not acceptable. A vote to leave gives more power to some people we already dislike.
I always have a concern that people will vote one way or the other for the wrong reasons - one of which is definitely those living in the past wanting to return us to the 'good old days' of the 1970s (probably my parents/grandparents generations), likewise some naivety with respect to the benefits the EU brings vs the true cost, economically and in terms of political/sovereign control .. which is something aged 18 and with little world experience you're barely going to be aware of.
In an era with so much social media influence, dictated largely by mainstream media and their respective backers - the decision will not come down to the true vote of A vs B, but most likely which group of stubborn or persuadable people is largest.
Lets hope everyone considers the impact to their kids, rather than based on old ideals of red, blue, left, right, nationalist, raving mentalist. This should be bigger than that.