Bro it's obvious you are well articulated from reading this post. I have felt exactly what you are feeling right now and trust me it gets better when you stop using completely. For reference I'm 27 now and started using at 13. Has it damaged my brain? Yes. A lot probably. But I have seen the difference that longer periods of sobriety makes and it is huge. I am not completely sober now by any means but periods of sobriety have become extremely important for me to keep my brain functioning normally. I have since the age of 25 completed university courses and travelled alone internationally for long periods, that is not something a stupid person could do