I have the same problem, but I do morning exercises every day. This is a good idea to go to the gym. I think I would like to go to gym, if I had any free time for this. What exercises will you do in the gym? How often will you sport? It is very important, how often you can do it. My advice is: Do morning exercises every day and you won't feel really unfit. Tell me about your now exercises.
Best wishes, .......... (name)