I've decided to do exercise everyday for 30 minutes. I will be doing like a circuit thing which consists of 30 jumping jacks, 5 press ups and 10 sit ups. I will just keep rotating those 3 exercises until 30 minutes has gone. I know it will be more effective to add more press ups and sit ups but i can't manage to do more at one go. So do you think this is good? Should I change anything? How many calories do you think I will burn in those 30 minutes? I am 133 pounds if that helps 