^This!!!! I probably should have written something short and sweet like Rob when I replied before, but I was trying to give you some tools like the BMR equation to get started. The bottom line is that MyFitnessPal or some other nutrition tracker is really pretty much mandatory. Nutrition is sooooooo important and often ignored or done incorrectly when someone starts an exercise routine. I know diets don't work, I know that some of the crazy exercise plans don't work either, but this does. I am female and lost just shy of 30lbs this way in conjunction with weights/exercise. I wasn't obese to start with, but the weight I did have stays off! I am also stronger and healthier overall. You can do it!
Best of luck!