I dont care how old you are. You can build muscle at any age. I cant stand hearing people who are over 50 saying that it is too late to build muscle and get in shape. I can show you the best ways to build muscle whether you are 13 or 63. Here is a video of Sylvester Stallone working out hard at the age of 62.
I dont spend hours and hours every day in the gym but when I do go to the gym I work out very intensly so that I am tearing down my muscles and then I eat correctly right afterwards to build my muscle.