how can i be really fit?

F.I.T.T.

Frequency- at least 30 mins a day, depending on what exercizes you do.

Intensity-How hard you do something--As hard as you can, but pace yourself so you can last longer

Type-Alternate each day. Lifting weights, running and sit-ups one day, swimming, bike-riding and push-ups another. Pick some that you can do, and make your own schedule to what works best for you.

Tendency- At least once a day, maybe 5/6 days a week. Take a day off so that you're not over-working your body.

Note: If you end up quitting this routine, all your muscle will turn to flab. Make sure this is what you want to do, motivate yourself so that you don't quit, and if you're going to keep at it, make sure you eat just as healthy so that you don't become inbalanced. Also, if you end up experimenting with drugs, alcohol and/or cigarettes, you will most likely end up working for nothing, and may work your way into a heart attack, or worse.

Also Note: Yoga is a very relaxing, stress-relief type of exercise that you might like. Maybe you'd like to weave that into your schedule?

Good luck! Hope this helps, and congradulations! You are the first teenager that I have met to make a good decision! Kudos to you. :)