I am under age 16. The research I did says that if a parent isn't able to come in person to the passport office, then they need to fill out Form DS-3053 and have it notarized. But what if neither parent can come in person? Can I get a copy of that form signed and notarized by each parent and bring them both to the office?
At the US Department of State website for passports, it states that if parents are unable to appear:
A third party may apply for the child's passport with a notarized statement from both parents/guardians giving that third party permission to apply for the child.
The statement must include a photocopy of the parents/guardians' identification. When the statement is from only one parent/guardian, the third party must present evidence of sole custody of the consenting parent/guardian.
In all circumstances, you must be accompanied by one adult, but it doesn't have to be your parents.