how to keep my brothers out of my room

this is gonna sound extremely immature and petty but i need help keeping my younger brothers out of my room. the door to the attic is in my closet for some reason, which means the only access point is my room. i dont know why, but theyre desperate to play in the attic. there is nothing in there and they know it, there isnt even a working light in there. theyve literally been in there before and theyre aware theres no toys, no stuff to do, nothing in there. my parents are no help so i need ways to keep them out of my room when im not in it

my door has a lock, but they know how to pick it, and its just been constant for the last few days. they do not respect the word no and ive caught them sneaking into my room when im not there despite me repeatedly telling them i dont want them going in and out of my room. its exhausting and i hate being too stressed to do anything outside of my bedroom because i know theyre trying to get into my fucking room again

i feel so stupid being upset over it because im a 19 year old guy and should be able to handle people in my room, and ive let them in before. i just hate it when people enter my space without asking and after ive told them not to. its not even like they have nothing else to do they have electronics and toys and can go play outside i dont know what their deal is