I think you would become obsessed with your health and it would do you no good.
If it told you that you didn't get enough sleep what are you going to do about it?
Would you feel guilty if you didn't reach your exercise target that day?
If you don't record your exercise regime now you don't need an Apple watch.
If you believe a fitness tracker would be beneficial there are cheaper and better options.
You can turn your phone into an exercise and sleep tracker and pair it with a cheap heart rate monitor.