Sounds like you have made the choice for fitness and you are headed in the right direction Oliviagilmore!
You do however, need to consider your nutrition. Exercise is only part of the weightloss puzzle. In order to lose one pound you must burn 3500 calories more than you take in but you should not cut calories drastically.
Every step that you take (literally and metaphorically) is a step in the right direction. It is great that you are taking daily walks with your dog and yoga is good for the mind body and soul. You should IMO cycle in the cardio and strength training dvds. Try not to take on too much at once and to warm up and strech before and after excercise. Weight loss is a slow process and it doesn't happen overnight. If it were easy, everyone would be fit. Keep your head up and have fun with it! I hope this is atleast kind of helpful!!