It sounds like the only thing you did wrong was over thought it. I'm 45 with my first drone, and started the same way. Just go easy on the sticks, slow & small inputs. And remember to breathe and have fun
I found last section on page 30-31 interesting. 'A certificated UAS operator must carry the certificate, which is a plastic card with a unique certificate number and personally identifiable information.' Do they send the plastic cards?