I'm 5' 4.5" and 215, a little taller and a little heavier than you, but I am also 23 and the health thing has been weighing heavily on my mind. I have committed to eating 6 small meals a day, staying away from salt, lots of fat, and massive amounts of sugar. I walk about half an hour everyday, to work, but I plan on adding another hour of cardio, gradually, mostly with my wii and cardio tapes. And some weight lifting/ resistance training. I want to be fit, rather than just skinny this time around. I hope to hear from you and your successes! Good Luck!