Hi Christie, welcome to FitDay. I've done the Shred in the past and it is great for toning up and you see results fairly quickly if you pair it with eating sensibly. However, I think the claim of 20 pounds in 30 days is stretching it a bit. Losing and keeping it off is a process that can't be hurried along (unfortunately). The rate at which you lose depends on your height, starting weight and age (basically factors in how many calories you're burning). Generally, 1-2 pounds per week is considered a safe and maintainable rate of loss, though if you're just starting out you might get a big drop of (mostly water) weight in the early weeks.
Stick with it and good luck! It is possible to lose the weight, and there's never a better time to start than now