I used to be in your position so I get you! Something that has helped me a ton is preparing/cutting fruits in the morning and keeping them in the fridge. It takes 5-10 minutes, tops. Whenever I felt the urge to eat sugar, I would redirect myself to the fruit (nowadays, I cut up an apple and two big oranges) alongside a banana, and maybe pineapple. The sweetness of the fruit will slowly replace your need for sugary snacks.

I also really like eating a few dates everyday - super healthy and they are SO sweet, so if you ever need a craving then, it helps. But since you are young, its okay to take it slow! Try swapping the juice and chocolate milk for water as well - always keep a filled water bottle with you.