When I was in your position one of the first things I did was to install arch. It is very similar to gentoo but you don't have to compile everything yourself which is just more practical in the beginning. You still have to learn all the basics and the arch wiki is one of the best of it's kind. I am myself to install gentoo as a next step but the procedures are very similar to arch. Also with arch you can reinstall the system in minutes (with enough proficiency) but on gentoo or LFS this depends on how beefy your computer is. With a regular desktop you will sit there staring at 5the compilation for quite some time which was the biggest drawback for me. It will cost you more time to repeat a process and for me the best thing on arch was to srcap everything and restart to try something new.

One last thing: You will always learn as much as you are willing to understand. You can install gentoo and arch withoit any problems by just following the great wiki pages but you won't learn much besides typing some commands. But doing some research wbile installing will help you far more. Also learning linux is a process. It's not only about the system itself but rather about the community it's culture as well as the philosophy behind it.