I'm on the opposite side of DC - up 270 in Frederick. I hope your daily commute is better than mine!
I know what you mean about being surrounded by people who don't (outwardly) care about weight or fitness, or by people who seem effortlessly thin. It is impossible for them to relate to people who have been overweight their whole life.
Good for you for making it about health. If you aren't in a hurry to get to your "ultimate goal", I would strongly suggest doing a weight-lifting routine. You CAN start no matter your weight, and it will definitely improve your overall health. There is no need to wait for goal, but it will slow your progress toward goal because you will be recomposing your body in addition to shedding fat. However, you will feel better and your dimensions will change faster than the number on the scale.
Up to you - whatever you do, welcome and good luck in your journey!
Most recent restart: 4/29/2013 @ 317.8
My plan: Standard Ketogenic Diet (pretty much Atkins Induction)