Good Luck girl!
My cousin and her family have moved to New York from the UK so I have a few tips for you. =D
Honestly it takes a while you know with VISA and passports and all the legal stuff. But after that it's pretty okay...

First I would say make sure you can live because living in NYC IS NOT EASY!!
Make sure you can get a job and that you make enough money to pay the rent because these NY landlords do not care! If you haven't got the rent well that's too bad they have no issues with throwing you out! =S
But that is the first thing I would say. Make sure you are financially stable! =D
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Second, If you're going alone be CAREFUL! NYorkers are hardly known for being friendly. There are some people there that can be just wonderful. I went there last year for a few weeks and the people I met where just so sweet on the Upper East Side. They were wonderful. Maybe it helps when you have money but whatever...
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Thrid, Save money wisely remember you need to live, food, clothes, etc
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Fourth, Living in NY you may be naive like I was. I thought oh yeah I'll get a penthouse apartment with 30 bedrooms and all that... Obviously not! =(
My aunt and uncle are pretty rich so they got a good apartment with 3 bedrooms but it's still just a small apartment and with 3 kids it's not easy. So remember you may have to start with a studio or a basement apartment but after a while you might get a better job and get a chance to move up in the world so it helps what job your doing.
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That's it I think.
I really hope this helps! And if you do move let me know how it goes because when I'm older I also want to move to New York City! =D
Hope this helps you

Good Luck

xoxo