All my life I was not thin. I wasn't in the habit of thinking about the food I was eating. At 35 years old I decided to change my life. I'm 1.7m in height, and my weight was almost 90 kg. I started to watch YouTube channels, and read books about fitness. I understood that our food contains fats, carbs and proteins, and you need to control all these nutrition components to lose weight. After 4 months my weight was 58kg. I felt good and full of energy. Then I decided to go to the gym. I have been going there for 1.5 years, my weight now is 70kg but it is muscle not fat. Eating differently and going to the gym are my hobbies now (or “healthy eating and going to the gym are my hobbies now”). You can do it too, you just need to learn about nutrition and exercise a little, which you can do on YouTube. Good luck.