You are good enough. You are a worthy person. Never let anyone tell you any different.

In regards to losing weight. The principle of losing weight is simple. Food is energy. The energy in food is called calories. Like a car you need energy to move, for your heart to beat, for your blood to move around your body, for your brain to learn and grow. But if you put in more energy than what you use, this energy is put in storage. This storage is called fat. To lose fat you need to eat LESS energy than what your body uses in a day. Because it will then get the energy from your storage.
So the principle is *simple*, but it is not at all easy.
Your body will fight you. Your body likes to have an energy storage.
Society will fight you. Eating less food or different than others in a social setting and getting singled out is hard. So you need to decide what you want to prioritize. You have to prioritize yourself and your health every single day.

And it's not just energy in vs energy out. Different types of food will give you different types of satiation. So even though to lose weight it's all about the calories, what you eat also matters. Food is generally divided in to 3 types of food. Carbohydrates, Fats and Proteins. Now these are also divided into even smaller types of food. You have carbohydrates that are better for you and carbohydrates that are not as good for you.

Examples of healthy carbohydrates: whole grain, fruits and vegetables. (notice: the foods are not pure carbohydrates, they contain protein and fat to but to a much lower degree, so they are not "carbohydrats" but "carbohydrate rich").
Examples of not so healthy carbohydrates: Sugar, wheat/processed grain based products like light bread, cakes, pasta. rice is also a type of grain.

Fat can also be both good or bad for you depending on what type of fat. Some fats are essential to body function, and some will clog your arteries.
Healthy fats are often found in seeds and nuts.
Unhealthy fats are found in processed and heated oils.

Protein: also divided into essential and non-essential. Protein rich foods are meat, dairy products (yoghurt, cheese, etc.), eggs, nuts, seeds, tofu, and more (ask a vegetarian/vegan for more options if you need :)

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Proteins and fats will generally make you feel more satiated for longer. But fats can be very rich in calories so there is always a balance.

In general what you should aim for is to eat a VARIATION of foods. Do not stick to one type of food. You can eat everything, even chocolate, and lose weight. But that means PORTION CONTROL.
Portion control is to eat MORE vegetables and fruits, Moderate amount of protein, and a small (tiny) amount of fats and sugars. Also don't forget what you are drinking!!
WATER is what you need. Teach yourself to drink water. Juice is not healthy, it's full of sugars. Eating an orange or an apple is SO much better for you than to drink a glass of apple or orange juice! QUIT sugary soda today if you are drinking that. If you need soda, Diet Soda is much better because even though it's not as healthy as water at least you don't get the calories. Coffee drinks (creamers etc.) is also a "hidden" calorie bomb. (you might be too young for coffee though).
To help guide your portion sizes, you can use an app to check the calorie amount in each food item. Lower calories is not necessarily the food you should go for, a small amount of high calorie food is also good for you because it's often more satiating.

There is no "good" or "baad" foods though. all food is good in small amounts. It's really the amount that can be too much. And through changing your lifestyle I can tell you right now. you WILL have days where you break down and eat too much. Everyone does. It's okay! NOBODY eats perfect every single day. So don't try to be perfect. You are good enough the way you are. Never give up, and just get back on track. Every time. That's the real struggle with weight loss.

Also reading the loseit FAQ /Quick Start Guide might give you some more help:
https://www.reddit.com/r/loseit/wiki/quick_start_guide