How can I have the best skin possible?

Hello so I am 19 years old and I am going to beauty school (either Aveda Institute, or Gene Juarez Academy, I am going in either September or December of this year). I have NEVER been a chain smoker nor a huge drinker. I like to drink every once in a while, I recently started smoking cigarettes, artificial pot, and hookah but I just quit and I feel alive, energized, and great!!!!! I always try to use all natural, chemical and paraben free products (soap, shampoo, lotion, conditioner, makeup, chapstick, sunscreen, body wash, deoderant, perfume, face wash, face masks, etc.) I found out that sun does a lot of damage to your skin about 2-4 years ago and started wearing a lot of sunscreen regularly. Where I live it is cloudy and rainy almost everyday. I basically stopped wearing sunscreen and stopped taking care of my skin the way I should. I want to have young, beautiful, youthful skin forever. In my opinion when I am not wearing makeup I look about 14-16 years old and I am 19!!!! I just need to know the best skin care routines, and the best ALL NATURAL PARABEN AND CHEMICAL FREE products! (When I buy my skin care stuff at the drugstore I try to get: Burts Bees, Aveeno, and Neutrogena.) And which comes first face lotion or sunscreen? How often to apply sunscreen, etc. I just need a lot of good information. Because I want to look like I am 20 when I am 35, thank you so much!!!!!