Working out is hands down a good idea, and you're in even better hands when you are working with a personal trainer. However, if all you do between workouts is sit around, you aren't going to see nearly the kind of progress that you would if you were leading an active lifestyle. That doesn't mean you have to spend your time doing push-ups, but rather, make your life something you experience on your feet.
Make activity a social reality. Go for a walk after dinner with the family, plan a game together outside or do the yard work together. Getting your housework done can also be a great workout- you'll bend and stretch and walk and scrub. Even if you just work at holding your abs or actively using your arm muscles while cleaning the floor you'll be accomplishing more. When you're out and about, you know the routine: take the stairs instead of the elevator, park further away and walk where you're going, etc.