Now, on to the advice.
Leave your expectations at home:
no, really, burningman isn't always a mind altering/ life altering experience - my second year was actually quiet and vaguely frustrating/disappointing for various reasons - if you expect things you will oft be disappointed, so try not to expect things
Everyone experiences their own burn:
Radical Self Expression, Radical Self Sufficiency. You define what you will and will not do, it is always your decision as to what you choose to take part in. I know people who have been bored and/or didn't get it and went home early from burningman - these people chose to spend most of their time in camp, under shade during the day, and huddled under a blanket in their tent alone at night though, so really, they chose their own experience, my point is, you are in control.
it's really just a big camping trip:
no, really, let go your expectations, let go your concerns - just bring the basics for camping, bring a good warm coat, sunscreen and water, and go walk around and say hi. drink your water, eat when you're hungry, sleep when you are tired and above all...
just be you and see what happens