Getting into the Dirt Bike Thing... Need Some Help.

Hey Guys. Ive just started to dirt bike, i used to mountain bike alot with norcos and Konas so i have some experience off road... kinda :think: . But im 6'2" and i weigh 175lbs... would a 250CC bike be good enough for me with what i wanna do? Like off road trails ( not professionally graded ) with a top speed of like 75-85 km/h... (40mph). Im not sure what i should get but i got a wicked deal on a 250cc but i dont wanna waste my money if its not right for me. If ne1 could give me any intel that'd be GREAT!!!!!! My dad says it should be perfect for what im doing with it and he used to bike alot so so far im believing it... but id like some other opinions. If u could post id appreciate it. Thanks!!!! :cool: