This information is courteously offered, no criticism or offense intended.
Because you indicate in the question that you parents will know if you open another bank account, guessing the existing account may have your parents listed as co-owners, which gives them legal access to the account information and the money on deposit. The existing bank account is considered theirs, so all mail which arrives at the home address they will open, expecting the contained bank information to relate to this account.
According to United States law, an individual twenty-one years of age is legally considered an adult, and can sign binding contracts, including opening a checking or savings account in their name and social security number (SSN). Suggest going to a different financial institution and opening a new checking account under just your name and SSN, so only you can access and use the money in the account. Using a different bank separates you from the exiting bank and the account which your parents can access.
Because your parents have had access to information on this account for some time, they will probably notice when you stop making deposits in and/or withdrawals from the existing account. Consider getting a Post Office Box so all of your mail will no longer arrive at the family home address, and be subject to the scrutiny of your parents. Use the Post Office Box for the mailing address on the new account. Definitely do not leave any stray papers or envelopes around in your room, and also keep close any ATM card issued to you for the new account.
Personally use a size 2 Post Office Box because it allows for magazines and other oversized envelopes to be curled up along with regular sized mail. If you are only going to use the box for letter sized envelopes, you may find the size 1 box sufficient. The Post Office branch will place in the box, along with smaller mail pieces, a key to a locker or a note for counter pickup, when larger packages are received.
Size 1 - X-Small (3" x 5 1/2" x 14 3/4")
Size 2 - Small (5" x 5 1/2" x 14 3/4")
https://www.usps.com/manage/get-a-po-box.htm
https://about.usps.com/forms/ps1093.pdf