In all honesty. Since its your first bike a 125cc 2 stroke will dust a 250 4 stroke and comes alot more equipped(forks etc.) for a track, a 250cc 2 Stroke for your first bike is wayyyyyyyyyy to much. If anything get a 125cc 2 stroke, you will be more than satisfied for a long long time, I modded my 125 pretty extensively and in a shorter track my 125 with me riding would walk on my 250 with me riding. The 250 just has so much power and on a shorter track you just cant open up the monster.

250cc 4 stroke is a waste of money IMO. Slow and gay is how I see it.

O btw. If you end up getting a two stroke, always carry and extra spark plug with you as sometimes they like to foul out while your riding in the woods they are only a couple bucks for most bikes. If your bike wont kick over its most likely a sprak plug not a blown motor