You'll really have to spend a lot of time working if you want to be successful. The successful agents have been doing it fir a while and have a big book of business and at that point can sit back and let the premiums roll in.
I worked as an insurance agent for one of the big company's out there while I was in college. I worked normal business hours but also had to do outside marketing for the agency (I wasn't the owner of the agency) and still get in my classes.
If you got started on the business young or took over Someone else's book of business, you can be very flexible with your time. But just getting starts is going to wear you out if you want to enjoy retirement