> non-trivial content
You mention "3D animation" and "game design" as areas of focus.
For the former, there are established learning paths, so perhaps quite easy to estimate when you'll get to a point where you're delivering industry-standard work.
For the latter (game design), perhaps the answer is a bit different. If you study game design at, say, university, the learning path might be a combination of reflective practice (studying games, writing critically/analytically about them), prototyping, making a bunch of games (including the final major project), and doing lots of experimentation (and maybe also going deep into a particular unexplored game mechanic, world building, character design, etc).
Even if you finish university, you'll still have to make plenty of games to hone your craft.
And the, for both of these areas of focus, to actually stand out from the crowd, would require something special. Maybe innate talent, maybe a new way of seeing the world. This is difficult to estimate.
(But perhaps you've been sculpting 3D models and making small games in your spare time anyway, and maybe you're already quite good, so who knows? :)
> charge for my work
You're competing with a lot of other people for gamedev work :-) Most gamedev programming jobs don't pay as well as other programming jobs. You'll be doing it for the love of it!
Someone I know worked at a gym, but made games in Unreal in their spare time, then did a 2-years remote masters in indie game dev, and got a job as a technical artist at a small indie studio. AFAIK he still just uses blueprints. I don't know how long he spent before university working on games in his spare time, but the 2 years of fast-tracking his knowledge really helped.