Answers
I suggest you proceed with Golden Visa process as a dependent of your parents before becoming 18. After expiring the five-year period, you may apply for residency according to the legislation applicable at that time.
Regarding the acquisition of Greek citizenship, please be advised that the applicant has to be able to prove seven years of permanent and legal residency in Greece, with a minimum 183 days per year, among other conditions, such as to keep a permanent resident permit of the types that are recognized by the law. On occasion of this communication, I would like to inform you that, according to a recent legal amendment, the permanent resident permit of a property owner or a permanent investor resident permit are included as final titles acceptable for naturalization of foreigners. In your case the best solution could be the property investment to be concluded on your behalf, in order to be entitled for the main benefits as above and your parents will be included in your application as your family members. In any case. the past three years will be counted in your time of legal stay in Greece.
Seven years of residency needed for Greek citizenship will be complete when you become 22 years old. Your plan is feasible. The only catch is you cannot work in Greece when you are included in the Golden Visa program.