s.d. on 95th Percentile Estimate?

Greetings all,

I'd like to estimate the 95th percentile of a distribution p(X) by
making N independent measurements of X. I'm assuming that the 95th
percentile of measurements is the best estimate of the 95th percentile
for the distribution.

Is this halfway reasonable?
Do I need to make strong assummptions about the shape of p(X)?
How would I arrive at the s.d. of the estimate, or some other
indicator of quality?

Thanks for your help