When we decide to lose weight or get healthy, we tend to try to change all aspects of our life at once, get overwhelmed at all the changes, get frustrated and quit. I've made that mistake MANY times. I'd try to start exercising and dieting at the same time and would give up after a week or two.
Instead, try changing one thing at a time. For example, diet. Take a month to focus on eating healthy and get used to the new lifestyle. Then add the workouts. You are more likely to stick with it if you don't overwhelm yourself with a complete lifestyle makeover overnight.
Don't set yourself up to fail. Don't expect perfection. Take one step at a time and you will reach your goal!