Some top students do not necessarily require validation from their peers because they're just confident in themselves. Doing well enough that others might call it a great accomplishment is something they are sure they can do; they believe in their own capabilities. It's kinda like... "I don't need you to tell me I can do it."
I think you guys look at pressure the wrong way. There is no sense in "stressing out". Nobody is asking you to explode an asteroid about to collide with the earth tele-kinetically. Whatever expectations they have, it's certainly feasible and far from impossible. Wearing yourself thin over it will only hurt you. Have some faith in what you can do.
Pressure is not something you should be fazed by. When I was in grade 6, I turned down a scholarship I earned and opted to go to a public school instead. At the time, I said to my parents, "it doesn't matter, I can manage regardless"; consequently, they not only expect I me to do well, but they pretty much consider it a given, my problem and not theirs. Many of the people in my school, acquaintances, friends, teachers, expect a lot as well. A lot of my friends, in discussions about year 12, predict my English study score to be 50 if not very close. My accounting teacher often hints expectations of the same. My English teacher said she wants to see my name in the paper next year (even though I pretty much sat through her classes and did my own thing for the entire year, which was usually sleeping or something highly unproductive). Often I hear that I'm expected to score within the top few at my school (which, to be fair, is not that big of a deal in a public school). My best friend expects me to get dux. I've made a promise to get at least 99, which I intend to keep. Another very close friend and the top student at my school in the '09 year that has been helping me out with preparation expects the 99.95. To do this, I cannot slip once, in a single one of my 10~ exams. The course I want to do requires a clearly-in of over 99. I also have 3 siblings, and I can tell that they'd be amused if I messed up. I have 6 subjects including enhancement accounting, and no 3/4 subjects in year 10 or 11 to back me up (combination of bad reports, my own negligence and the sub-par nature of my school). To top it off, I don't plan on putting any course on my preference list below 95. You're much more likely to survive if you're not afraid of crashing into the side of a mountain. I know this sounds like a whole lot of bravado (and I wouldn't normally say all of this to anyone; I never have), but I think it's necessary to make my point. Erase the doubt from your mind. If you don't have the mental fibre to do so, build it. I cannot explain to you how it feels and the difference it makes to believe in yourself with absolution any better than this.
Oh, and I'm not a top student (if anything, just incredibly arrogant and conceited), nor do I make that claim. But what does that matter? Tomorrow is not decided by what you are and do yesterday, but what you do now and later. I'm not going to sit here in the middle of the night and argue with people over the internet as to how talented and accomplished I am. We'll see once the year is done.