It's fascinating to look at the result of such life-long training. 20 years ... ... you've strted early!
Hehehe. "So sieht´s aus." I started when I was able to hold a pencil. My dad is a graphic-designer, too. He advanced me since I was a little child and taught me about things like anatomy and perspective. As a freelancer, he worked at home a lot, and I liked to watch him. I started playing with Photoshop when I was 12. Knowing your tools well is a big help.