Welcome to Health Care Magic. Thank you for posting your question.
I can understand your concern.
See , at your age it is easy to shed off the extra pounds by exercising . Imagine if your age was around 60 . Could you do that ? NO.
So you do have an advantage.
I can understand it is difficult to start running around and losing 15-20 lbs in a single day. But , yes , there should be a start. At your age , you should not be facing problems while walking , but you are having them, so start fast.
Now , let me help you out on a plan :
Try to maintain a balanced diet with cereals ,
proteins ,loads of vegetables . Try to eat around 4-5 fruits a day.
Keep away from fried food , soft drinks , chocolates .
Have small meals at regular intervals.
Drink loads of water.
That's all about the diet.
It would be great if you could add to that a bit of physical exercise and cardio workouts like walking and jogging. Walk for at least 40 minutes a day
Walk at a slow pace and then gradually increase.
It is not difficult at all. You are just 14. You can do it.
Stick to this plan for 6 months.
Post any other question. We will be happy to help.
Have a nice day. Regards.