@Casey
The P40 is also among the planes that are pretty good for beginners. You can even turn with AI Zeros in it (don't try that with human piloted Zeros...
). I wouldn't go head on in any aircraft that doesn't have cannons as armament and even in one it's still a pretty risky thing to do as CCIP has already pointed out (especially if the other guy has cannons).
I would recommend you to learn taking off and landing first (well, Oberon will probably disagree here but still...
). That way you'll get to know the aircraft and it's characteristics. It doesn't hurt to have a little dogfight every now and then in between of course.