I'm putting on castor oil on my face now.
I recommend (because I'm 37 and I've done it) for everyone to stay out of the sun and wear sunscreen and reapply every 2-4 hours. Let it settle in before going out. Also start taking care of your skin early. In your 30 start applying hyaluronic acid, vitamin C, and also over the counter retinol (vitamin A) products.