Body Balance is a beautiful class to start with - my next bet would be with Body Pump. Just let the instructor know before the class starts that you're brand new and they'll set you up with light weights and watch your technique throughout it (dont stress, it'll be worth it in the end).

These are the two class which will give you quick results and a toned body. Stick to pump x 2 each week and balance 1-2 each week too....Then cardio Aqua aerobics is always good fun too