Be reasonable about what you are capable of. Do it for yourself, not anybody else. The only way you will truly commit to a new lifestyle is if you really want it to happen. If you received a gift certificate to Lifetime Fitness Center, carefully consider your motivation for starting on an exercise program. Find something you enjoy.
Some people prefer aerobics, others like weight training.
Perhaps you will find yoga suits your needs. Lifetime Fitness Center membership provides you with a custom designed program based on your needs. As your endurance builds, modify your program so you continue to feel challenged by exercise. When you reach a certain level, you'll need to increase your intensity or duration. Lifetime Fitness Center staff will re-evaluate your program and help you set new goals.