Under Washington's emancipation laws, anybody aged 16 or older can petition for emancipation.
Quote Quoting RCW 13.64.020 - Petition for emancipation - Filing fees.
(1) A petition for emancipation shall be signed and verified by the petitioner, and shall include the following information: (a) The full name of the petitioner, the petitioner's birthdate, and the state and county of birth; (b) a certified copy of the petitioner's birth certificate; (c) the name and last known address of the petitioner's parent or parents, guardian, or custodian; (d) the petitioner's present address, and length of residence at that address; (e) a declaration by the petitioner indicating that he or she has the ability to manage his or her financial affairs, including any supporting information; and (f) a declaration by the petitioner indicating that he or she has the ability to manage his or her personal, social, educational, and nonfinancial affairs, including any supporting information.

(2) Fees for this section are set under RCW 36.18.014.
The petitioner must prove at a hearing by "clear and convincing evidence: (a) That the petitioner is sixteen years of age or older; (b) that the petitioner is a resident of the state; (c) that the petitioner has the ability to manage his or her financial affairs; and (d) that the petitioner has the ability to manage his or her personal, social, educational, and nonfinancial affairs." RCW 13.64.050.