Having a set goal is great and if your goal is to get fit then the type of exercise will matter. If what you selected did not matter then you may simply complete push-ups everyday for the rest of your life and this would not be something I would suggest. You need to keep your body balanced. By balanced, you should have an equal amount of cardiovascular activity mixed with strength training to be sure your body runs efficiently.
An example training day may include: Warm-up for 5-7 minutes with some form of dynamic warm-up. Following, complete 12-15 minutes of cardiovascular activity such as using the stairmaster. Next, choose 4-5 exercises and circuit through these 2-3 times. Lastly, be sure to cool down with proper post-workout flexibility stretching.