Naji: That's not completely true. And maybe your first question was wrongly formulated.
It must be notified that that 95-5 percentage applies to independent game developers.
The game making industry is the strongest industry worldwide, making more than the movie industry for the past years.
In this industry, a lot of major companies offer more than decent salaries to their workers, namely developers, assets producers (graphic artists, musicians/sfx designers,...), etc...
Some people come out of schools where they learn those crafts and make a pretty decent amount of money in the next years.
If you want to embrace the game making career, you can select that path and enter the industry in big companies.
Now if you prefer/chose to go the independent road, it might be a safer road to indeed have a side-job that will make sure you have some income no matter what. But it's doesn't maybe make it always easy to keep on making game, because depending on the "day job", you have to struggle with fatigue, demotivation, etc...
Once again, you're still young, and at your age, you could just take advantage, learn/make as much games as possible and work well at school since the skills you learn there can be poured into your games anyway.
Then in a few years, you'll be able to make the point on what you know about making games and if it is worth it for you to go the independent road, or maybe try to join the industry in a "big company".
Once again, and has already been told to you in other threads you're so young, you have time on your side.
I see you going through those forums asking a lot of questions, apparently serious and enthusiast about making games, but it sounds like you don't really take in the answers given in the end.
At your age, make games, don't bother about the rest.
Listen to the feedback given on your games and improve them based on that feedback. Don't bother about the rest.