I understand your decision and wish you the best of luck, but the Peace Corps. is always available to allow to assist villages and towns in third-world countries by giving children an education, building houses and schools, irrigation systems, etc.
It is a lot of hard work, but it'll be about enough work you'd have to do in the Marines. Plus, you'd have less risk of deployment into a war zone.
But, if you still want to go into the Marines, I wish you the best of luck in your future service. You'll be doing a great thing for your country.