The incredible shrinking woman?

I'm proud to report that my short term goals are going splendidly.  And by achieving my short term goals, I'm working on my intermediate goals. And those intermediate goals?  Yup, helping me out with the long term goals.  Funny how that all works, no?

All of my goals really center on my health and fitness, but in the grand scheme of things, its improving my quality of life.  I feel this overwhelming sense of empowerment since going gluten-free.  I took control of my health and have honestly never felt better.  The depression has disappeared.  I have more energy and zest for life.  So really, improving the health and fitness is just building on that feeling.  And if I can take control of my health, and I can rid myself of depression that has had it's grip on me for years, it shouldn't be a huge leap to rid myself of the extra weight I've carried around with me for my entire life.  I'm not saying it won't be difficult and a tremendous undertaking with setbacks and frustration, but it's a challenge I'm more than willing to take.

My long term goal is really just one, in terms of health and weight: I want to get to 150 lbs.  It's a healthy, manageable weight for my height of 5'7.  It will be a long, long journey from where I am now to 150, but it will be worth the time and effort.  And really, I'd be happy with 165.  That's at the very end of the "normal" range for me in terms of BMI.  But 150 is the ultimate goal.  That, and a single digit dress size.

My intermediate goals center around a few different events.  The first is on May 3rd.  I joined the Austin Junior Forum and May 3rd is the fancy, cocktail attire dinner they hold to introduce new members.  So this chick will need a cocktail dress.  Then, one month later on June 4th, my friend Breanna is getting married in Colorado.  It will be the first time I see a large number of my friends in well over a year.  Once again, will be wearing a dress.  Right now I wear an 18, sometimes a 20.  (Sigh.)  By the time I go shopping for these two events, I would like to be down to a 14.  I'd even be happy with a loose 16, but a 14 would be ideal.  You know why?  Because most stores carry up to a 14.  I'm not going to put a weight loss number on this goal, and say I must lose X amount of lbs. to get to a 14.  But I have the thought it will be at least 50.  I've had a good start with about 15 in January.  But I will have to bust my ass to get there.

Any opinions, advice or general comments are appreciated.  Do you think it's doable?  Impossible?