I am thinking of getting my first dirt bike soon. I am 6 feet tall and 150lbs and 16 years old. I would be riding it mainly on trails, sand dunes, fields, and a little bit of motocross track. I have ridden dirt bikes before but im not to good. I dont think i will be racing unless it is just for fun against my friends. I will be doing some of the work on the bike myself. I have no preference to any brands or 2 stroke or 4. I will probly be buying the bike used. Thanks.