Newbie dirt bike rider. NEED OPINIONS?

So i recently (2 months ago) started to ride my friends 2 stroke honda cr80. This was the first bike I had ever ridden with a clutch. I have gotten used to using a clutch and shifting etc, and I generally feel very comfortable on this bike. Now here's the problem, I'm way to big for this bike. I'm 5'9" and weigh 180lbs. I'm buying this a bike for myself sometime this summer and I was considering buying a 4 stroke 250 (a trail oriented bike) do you think this is a good or bad idea considering my experience. Oh also i should add that i would be learning how to ride this bike in a big empty grass field. Feel free to ask any other questions you have. Anyway thanks for your help.

You need to have the bike fit you, and you need enough power to get up hills without stalling. The 250 should do well for you, until you are ready for more power. Back when I was 5'5" and 125 Lbs I had a great time dirt riding a Kawasaki G3TR 90 ( 2-stroke)- climbing, flying, sliding and sometimes falling down. Years later I settled in on a CL 350 Honda, which I didn't dirt ride, but commuted on, street and freeway for years. The Kawasaki A7 Avenger was my dream, but I knew I could not behave on it.