Sun Damage from Sun Exposure During Teens?

During most of my childhood I was shielded from the sun with clothing,hats, umbrellas and sunblock due to the fact that I'm Celtic, very pale, and burn easily. I also spent most of my time inside until my early teens, when I spent a bit of time outside, though a lot inside.

Thing was, in most of my teens I didn't use sun protection, except sunny holidays. About when I was 18-19 I started wearing it every day. I am now 21, I wear spf50 on my face every day in summer, and spf15-30 all year round in winter. How much sun damage do you think I have?