If you wear sunscreen on your face, neck, decollete and hands EVERY day (I use it instead of a moisturizer), you'll age beautifully. Make it a habit. Rain or shine. Wash face. Apply sunscreen (not a moisturizer with sunscreen in it, but a real sunscreen made for the face. Neutrogena Ultra Sheer Dry Touch is the one I have used for a very very long time). I look younger than some of my friends who are 10+ years younger than I am, and this is because of the sunscreen.
The UVA rays are what age you (and cause skin cancer) and they're the ones that are always present - rain or shine. They are even present in fluorescent lighting and they go through glass (even auto glass). The UVA (aging) rays go deeper and do more damage that takes years to come to the surface. My patients, when explaining to me why they don't wear sunscreen, would say they were never outside (and I'd ask how they got to my office), or that they spent most of their time in the office (under fluorescent lighting). It's a hard concept because we're used to thinking that only the UVB (burning) rays did the damage (because you could see it), but while they still do damage, it's not nearly as bad as what the UVA rays do.
Take it from me, in 20 years your friends are going to be looking at you and wondering how you got the good genes for skin - and all you will have done is used sunscreen EVERY DAY. Rain or shine. Even in the dead of winter when you're not leaving the house.