First off, the schools on T.V are a little over exaggerated. You MAY run into those type of schools, but you most likely won't. They aren't split up into categories, you're basically friends w/ who ever you choose to be friends with. Almost everyone is accepted, unless you're in a school in the ghetto, or a school in the rich areas.
Running into celebrities, only if you live in LA or NYC and even then it's not common. If you're in the right part of L.A then maybe you will. The environment is not the best, in the large cities, it's dangerous to walk the streets in the middle of the night because there are homeless people sleeping all over, people who would do anything for some money (possibly stealing it from you). So even the beautifulest parts of the states are dangerous and not what you see on t.v
NYC looks beautiful, but what they do not show is the truth (homeless people, drugs, murders, gangs). Cities on T.V aren't exaggerated, they just aren't showing everything.
Stereo types almost don't exist, either your cool or your not. Most people who wouldn't be considered cool are those who wear walmart clothes , and walmart shoes.
America is a great place to be, as you hear.. it's the land of opportunity. I've been living in America for 18 years. If you plan on coming to America just come with a plan, because fast food and retail isn't a great first job for a new comer. Housing is sort of expensive, so don't aim directly for NYC or Los Angeles... they're expensive.
The reason I love America is because it is more free, it has more diversity, and we have more opportunities. Although not everyone has "liberty and justice".. it's still not a bad place.
Now Australia, I think of a huge zoo with Kangaroos and Koala bears everywhere lol..