How long will it take me to lose 15 pounds?

i am a 15 year old female, about 5 feet 5 inches tall, and i weigh 135 pounds. i eat 3 very healthy meals a day, and i jog on the treadmill for 45 minutes everyday, at about 4 miles per hour speed. (so far this is really the best i can do on the treadmill.) if i can keep up this routine, about how long will it take me to lose about 15 pounds? any suggestions, encouragement, or motivation will be greatly appreciated!! THANKS!!

here are just some suggestions to cut back calories. switch the coke to diet coke, or better yet, water. 8 glasses of H2O a day will not only fill you up and keep you from being too hungry, but water also keeps your organs hydrated which in turn helps you burn more calories. and you can switch milk to soy milk, rice milk, or almond milk(has only 40 cal a cup and is easier to digest). and try to reduce cereal intake (its loaded with sugar and refined carbs, which break down into sugar) and replace with oatmeal which is more filling and helps fight stomach fat. and eat more veggies and fruits. try not to use mayo on sandwiches, its all fat. instead use hummus (or i just dont add anything). and use whole grain breads for complex carbs.

breakfasts:

1)mix and fry (use nonstick cooking spray instead of butter)
3 egg whites- 51cal
1 mozzarella string cheese- 80 cal
diced 1 roma tomato-30cal
=171cal omelet

2) cook one instant cinamon oatmeal pack-120cal
dice up one apple-90cal(and heat in microwave with a little bit of water)
mix apple onto oatmeal=210cal

3)put in a bowl:
1/2cup nonfat yogurt-60cal
cut up half a banana-60cal
4 medium strawberries-16cal
mix and enjoy:136 cal
(u can use any fruits really)

4) toast 2 multigrain waffles-200cal
cook 2 eggwhites without any butter-34cal
put eggs inbetween waffles and eat like a sandwich:234cal

5) first dice one banana and freeze it-110cal
then put in a blender
with 1/2cup soy milk, 1tsp of vanilla and cinamon-50cal
make smoothie:160cal
(can add 1 tbs of peanut butter for total of 260cal, or add other fruits)

ok so… the best way to boost your metabolism(which will make you burn fat better) and reduce hunger during the day, is to eat how i do: I eat about 200 calories every two to three hours, starting in the morning around 7:30 am to no later than 7pm. never eat after 7 (6 is best), unless you plan on staying up all night, for your metabolism slows at night because its preparing to sleep. .
oh and eat a ton of veggies because they are very filling and low cal. fruit too. some other low cal foods: nonfat cottage cheese, lite jellos; cheese sticks; yogurts; soups; or tuna, grahm crackers, kix cereal, pria power bars, soy, etc. if you like almonds, try almond milk instead of regular milk, it is easier to digest and the unsweetened kind is 40 cal per cup.
Oh, and because you get to look forward to another mini meal in 2 hours, you will be less hungry and less likely to snack on things. especially because you will be full on water too, drink 8 glasses a day. if you eat 200 cal every 2hrs from 8:am-6pm you will only consume 1200cal in a day.
but dont eat less than, at the very least, 900 cal (though most suggest no less than 1200) because then your body goes into starvation mode and stores everything you eat into fat for energy. so even though youd be losing weight, youd be losing muscle but keeping fat. and if you binged or started eating more daily then youd gain the weight back twice as fast.
and it is a good idea to buy some 3-6lbs weights and do simple exercises to build muscle and look toned. And the more muscle you have, the more you can eat in a day because muscle burns fat even when you are just sitting. Like 3 days a week do 2 sets of bicep and tricep curls, and then 2 days a week do squats, lunges, crunches, etc. an add at least 20 min of cardio daily.

I hope that was helpful