Installing Gentoo, for the first time, especially as a newbie to linux, is like the jump program in The Matrix movie.

"Everybody fails the first time."

"But what if he doesn't?"

Even if you're not "the one", the attempt would sure be a great learning experience. Alas, that was specifically stipulated against in the OP's criteria, on the first line:

I don’t want to go on a full learning process from the start