Is my brain too crowded or is this all normal?

this will propably sound stupid because its normal but im 14 and male. i have a very overactive imagintion too. often, infact all the time i have trouble keeping my mind on one idea because it either links it to something else or something better. and when im in school i dont need notes because i remeber everything. i feel as if my brain is far to crowded and i dont think a am able to achieve my brains potential. is this normal? thank you.