Aunt Promised My PC Away

AITA for refusing to give my little cousin my gaming PC after my aunt promised it to him?

So I (17M) built my gaming PC over the last two years. I paid for most of it myself from

birthday money, mowing lawns, and working part-time. My parents helped a bit with the GPU

for Christmas, but the rest is mine. I use it for school, gaming,

editing videos, everything. Last weekend my aunt, uncle,

and their son “Jake” (9M) came over. Jake is… a lot. He immediately went into my room and

started touching my PC, pressing keys, opening games, etc. I told him

not to because some of my stuff is expensive and fragile. Later I overhear my aunt telling