kimbo you really don't have anything to worry about. Even if it were within your genetic potential to get huge muscles starting to train at 46 would make it doubtful that you would ever get huge. Unless you are naturally very muscular than you will never look like a bodybuilder however hard you train with resistance training.
All you will do is get the look that many call "toned", which is just development of the muscles. Nearly everyone that trains with resistance will simply look more athletic and better, not huge. And if you did begin to get large muscles then you can always just stop the traininig, and your muscles will slowly shrink back to the size they were.