I have to agree with the info provided to you already. It may not be the answer you are looking for but what is happening with you is normal for your body.
Quote:
-either a breakfast item (muffin/banana bread, etc), some cereal, or fresh fruit (apple or pear)
-lunch of sliced white turkey and American cheese on whole wheat bread, a water, a breakfast/granola bar, and a chip/goldfish/pretzel snack bag
-after school snack of a few pretzels, an apple w/ pb; usually nothing big
-dinner of whatever mom makes! typically meat or chicken, starch, and vegetable/fruit or Caesar salad
-dessert: I'll have a cookie or whatever we might have, or just a bliss chocolate square or something
Right now you shouldn't think about dropping calories or other extreme weight loss measures at your age or weight. What you can do is focus on eating healthier to make your body more efficient with the fuel it is given and to feel better. Depending on the amounts you are eating (you didn't provide measurements), you might even be under eating which could put you in starvation mode.
I developed my eating disorder and body obsession around your age, 12-13, I am now 40 years old and have been fighting myself my entire life. It is very serious and can cause life long health problems. Like others said here I wish someone had told me back then that I was normal. I had the issue of being overly curvy and full busted at your age. I took it as being fat, ugly, undesirable. I wasn't, I was normal.
If you would like to do something for yourself and your health I would focus on eating healthy and continuing the exercise that you are doing.
Instead of (muffin/banana bread, etc), some cereal, granola bars, or pretzels, you could try replacing those items with lower carb choices link lean cubed meats, egg whites, cheese. You could add in more veggies that are fresh, steamed, or canned-not loaded in extra calories.
There are alternatives to some choices, my highschool aged daughter has changed many of her habits..instead of a bag of chips she now eats a single size serving of microwave smart pop popcorn, or plantain salted chips. There are options like that. For desserts instead of cookies or ice cream she now has a sugar free fudge bars, or fruit pop. She has replaced sodas with flavored waters. My daughter still loves chocolate and also pretzels, to help her I have purchased 100 calorie packets of dark choc covered pretzels. For several months two of my kids have been eating a great deal of greek yogurt. Not the high carb/sugar kinds but either the light versions made with splenda that are 90 calories a serving, or using plain real greek yogurt and mixing their own splenda and fresh berries.
You can not deprive yourself of everything, there are still occasions where there are french fries, birthday cake, things like that, but instead of telling my daughter that she can't have them she has a smaller amount of them and less often. You need to make sure that during the teenage years you are getting enough vitamins, calcium, healthy fats, etc. to help you grow properly and supply all the correct nutrients.
Also, using the stats you posted I looked around on the internet and this is what I found.
"A 14 year old (female) child who is 120 pounds and is 5 feet and 3 inches tall has a body mass index of 21.3, which is at the 71th percentile, and would indicate that your child is at a healthy weight."
"A child/young adult is considered overweight if they have a BMI over the 95th percentile for their age
at risk of becoming overweight if they have a BMI between the 85th and 95th percentile for their age
underweight if they have a BMI under the 5th percentile for their age
And a child has a healthy BMI if it is between the 5th and 85th percentile"
According to the multiple charts I compared your stats to it says you are at a normal weight. I have three teenage daughters, each a different height and weight. Two of them are tall and build very small or slight framed, the third is built with a very large frame, they are all different. Two of my daughters are either your weight or more (the older being 140lbs). I also have two sons and they are of different weights as well. My two smaller daughters eat nothing but garbage and are not healthy. Yet my other daughter who is larger tests healthier than her sisters because she eats healthier. She has also lost weight this year after weighing in at 230 lbs. I took her to the dr and even at that weight the dr stressed she should not focus on losing weight but on making better food choices and more exercise. She is now almost at normal weight without any major changes.
There are a million different body types and builds. I hope that you do not become obsessed with your own like I did and develop an unhealthy view of yourself or your self worth. Do not compare yourself to others or put pressure onto yourself that shouldn't be. Focus on being happy, healthy, and active. i wish I had had that advice at your age. Using the charts I found you are far from being overweight. You sound healthy and active. Have you spoken to your mother about what you are thinking about yourself and your weight, or even discussed it in health class at school? There is always someone that will listen and you made a good choice to get input from other people.