I would definitely either be an Airbender or Firebender, not really Earthbending or Waterbending. As Axle mentioned, Earthbending is stubborn, and I can be rather stubborn, but I think moreso I'm able to go with the flow unless something I'm particularly passionate about is involved (like Aang was in the series). I'd definitely not be a Waterbender, as I find Waterbending to be very weak and uncomfortable as far as fighting goes. I would say Fire is the most powerful and fiercest element, which is why I could also see myself as a Firebender. I'm aggressive and sometimes shortsighted.
However, I would say Air more closely identifies with me for a number of reasons. Firstly, more Airbenders are born in Autumn than in any other season, and I was born in October. Secondly, I'm more similar to the Airbenders' style of fighting than the Firebenders'. Although irl I'm more of a strength or power kind of person because of my body type, my ideal skills (if I ever got the inspiration to work out) would be speed, agility, and mild strength, but not brute force alone. My style of fighting would be more of a flashy/showy kind, and Airbending features a lot of cool moves that are effective against enemies.
As far as the philosophy goes, I would definitely say I'm an Airbender. I would love to train myself to be mentally connected with nature and to be more steady (which actually also pertains to Earth). I think Airbenders are the most spiritual and most detached out of all the elements, and I would certainly identify with that.