Good idea to document determination. - Particularly if you conclude you are not subject to the rule. - Not a rule requirement. See Section 2.4 of SPCC guidance document. http://www.epa.gov/emergencies/docs/oil/spcc/guidance/2_Applicability.pdf.
The age of consent is eighteen. With parental consent, parties can marry at age seventeen with the exception that if one party does not have a parent who resides in the state and one party has been a resident in Oregon for at least six months, then no permission is necessary.
As far as the world goes with the age of consent, the US is among just a handful of countries who have the age at 18 years of age, most other countries have a lower age. In Canada for example, the legal age for sexual relations is 16 years of age. Many of us here in the US would be surprised to know that many states have a lower age of consent than the standard 18 years. Two thirds of US states have an age of consent at 16 years of age, many with certain restrictions. I suspect Jared Fogle is in more hot water for the $100.00 payment for sex to the 16 year old girl than her age since in Indiana, the age of consent is 16.