i believe Nic's advice is right. if its not stated in a Will left by your mother, then your aunt is legally the POA and has rights to it. Now, if you are 18 AND your mother stated in a will that that stuff is yours ONCE YOU ARE 18 then you need to call a lawyer.
btw you could contact a lawyer and go for a consult. this will cost you about 50 bucks or so.. and they can tell you legally if you have claim over anything-word of mouth is not good enough.