Best dirt bike for a 14 year old boy?

I am looking to buy a dirt bike, I have some experience in riding, since I was 9 but not very often and only on farms and trails. I was thinking about a 200 but I'm not sure. I am 5'11" (180cm) and 85kg. Also 2 stroke or 4 stroke? I like the power of 2 strokes (never ridden) but again, looking for your advice. Thanks for your help! :)