Hey Tyme,
A little personal note. I dove as a young man, and then left the sport. I came back as a fat guy, and realized what a demanding sport this can be at times. I decided to lose some weight and lost 45lbs. I am not slim, but I am working on it. With that said I AM DEAD SEXY!
Now on to diving. If you are not strong as hell you will have issues moving the weight it will take to sink you. You will have to move your tanks and then climb out of the water with your tank and the extra weight you carry for bouyancy (negative wt., you have to sink somehow). This is going to be hard on the body, especially the knees.
Do not be discouraged. I would even carry your extra load the first few times..........until you were absolutely addicted and had to get in shape to continue.
Good luck, come diving and I will have a salad with you after the dive!
Joe