Please, whatever you do. Stick with it. The first two months are the hardest, and after that its all cake. You'll begin to WANT to workout, because if makes you feel bette throughout the day and maybe following day. I know i try to not go more than 2 days without my jogging, or ill start feeling down, start feeling fat even. :P Funny i still weigh the same on days i workout and feel good about my body, on days i eat bad or don't exercise i feel fat. :P So i try to exercise 4-5 days a week, giving some rest days do to weight training, and its just good to give your body a break to recouporate*.
3 days a week for 30mins is an excellent start. Stick with it, just remember its only 30mins outta your day, and after the 30mins is up, you will feel like you didn't even do it. I know sometimes i don't wanna jog, but after i do for 30mins, when i get home take a shower, its like in the past, and was quick. Dunno if you know what im saying, but whatever. :P Just stick with whatever you do, that is the best way to lose weight and get in shape. I have lost over 60lbs and gained tons of muscle mass, im about 10lbs to my goal weight and im siked...although these damn last 10lbs have been on me for 4 months...anways..good luck, and keep up with some updates.