I am a first time dirt bike buyer. what would fit me best?

[urban14]

i am 21, 165 lbs, 5' 8. this is my first time ever buying a dirt bike. i have no experience and i have never ridden on a dirt bike. what would be good to start of with? i'm on a budget though so im looking for a bike that is not too expensive.. my price range is between 2,000 and 4,000.