I have been doing about and hour of stationary cycling 4 times a week, and have been hearing that it is a good exercising maching for the lower body, but for loosing weight will it burn fat everywhere?

Yes, stationary cycling will lose fat all over your body and will moderately build up the stength in your lower body.

Depending on how hard you go during that hour, you can lose up to 600 calories / hour. If you don't eat anymore than you had been eating and if your weight had been steady, you will lose approximately 2/3 of a pound per week which is not bad and you'll be stronger cardio-wise.

Is that based on the 1 hour of cardio exercise per day? Because I only do 30 minutes per day of stationary bike riding, at an average of 23-25km/hr.

Will I achieve the same results, or be able to remove the layer of fat off my mid-section? Thanks. Btw, I'm only 16 years old, if age is a issue.

Yes, the bike can be used as ONE of the tools to an approach to fat loss however you have to make sure that your diet and weight training are in check as well.

Welcome mate! The speed on a stationary bike is only one factor along with the resistance. If you go hard enough on your stationary bike, you can burn 300 calories in 30 minutes.

Don't only use the stationary bike on the same time intervals every week. You should mix it up. If you're not a runner or swimmer, jump on the eliptical or stairmaster instead of the bike. Keep your body guessing and trying to keep up with you.
Also, vary intensity. If you ride the bike for the same amount of time every week your body will expect to do that and it can save energy (fat) in preperation for the workout. Go for a long period of time with medium reisance some days, and then crank on it with heavier intensity other days, and mix things up.

It's true that cycling on a bike will tone your legs, it is also true that cardio activity on any machine will help you lose fat all over your body.
If you're looking to tone/gain muscle in other areas of your body, you will have to work on those!