Exercise will definitely lower blood sugar and it takes some experience to find out how severely your body reacts to different kinds of exercise. I like to run and that drops my blood sugar A LOT in a very short time period (same with badminton for some reason). Just be sure to check before you exercise and make appropriate adjustments (eat a snack, give less insulin before you exercise, etc.).
I was diagnosed when I was 4, about 11.5 years ago so I'm pretty experienced with diabetes. I can't really imagine my life before diabetes but I can imagine the great stress you're under having to adjust to a completely new routine. It's awesome that you're here, because if you have any specific questions, want some support, or just want to vent, we offer open ears (eyes...lol). I'm sure you've worked with your endocrinologist to establish a strict routine with testing, insulin dosing, and maybe carb intake. If you stick with it really well for a few weeks, it will become second nature to you - you just have to endure it for a while and then it won't seem like such a big deal. Make sure to tell your friends and teachers/coaches/other adults you work with so that they know what to expect and what your needs are. Don't try to hide it from people who you interact with because if something bad were to happen to you, they could always be there for support. You may want to look into a 504 plan for school, if you haven't already. It allows you to retake or reschedule tests if your blood sugars are not in range before a test and lets you eat in class if you have to, check your blood sugar there, etc.
It's great that you're here and we are here for you if you need it!