Things that I would tell to younger me before I switched to GNU/Linux:

0. GNU/Linux is an excellent and easy operating system to use as a replacement to Windows for laptops or computers. It depends on distro too, I talk at least about begginer-friendly distros like Mint, Trisquel.
1. GNU/ Linux is easy to install, at least begginer-friendly distros.
2. As a begginer, start with a Debian/Ubuntu based distro. Because there is a lot of support, many software in repositories (apt), many tutorials on internet, many .deb software to download online. After you get used to it, you can try rpm distros (which run .rpm software, like Fedora) or even other types of distros.
3. Using terminal, at least for basic commands, is really easy. Like sudo apt update/upgrade/remove/purge, chmod +x [file].
4. You can use Linux even without terminal (what I said above can be made through a package manager interface which is already installed on most distros, or using 'right click-properties' for file permissions).
5. There are a lot of great replacements for Windows-only programs (browsers, office, text editors, photo and video viewer etc.).
6. You can run Windows software on Linux (using Wine), if you really need to.
7. Gaming can be made on Linux (a lot of native games, plus Steam offers Proton to run Windows games on Linux). You can verify how well games work using this website: www.protondb.com
8. There is not a black-and-white situation. You don't have to quit Windows forever. You can keep it in dual boot and use it only when you need software that doesn't work on Linux. For example, a Windows game that is running bad on Proton in Linux.
9. There are a lot of desktop environments (Gnome, Mate, KDE, Cinnamon, LXQt etc.), so your system can look how you want to. My favourite ones are Cinnamon and Mate.
10. You will feel great that you use a free and open source system and support small players in this area, instead of using a monopolistic closed system.
11. People will think you are a really advanced programmer, tech person (quite funny).

Let's talk about disadvantages now:

1. Changing anything, including an operating system, is intimidating. You will think you will never get used to the new system, software, its way of installing apps etc. But you will, quite fast.

2. Some Windows apps may not work, or work bad. It didn't happen to me, but I am quite sure it might happen. So you better make some tests of Windows apps on Linux before.

3. If you choose automatic partitioning when installing the distro, it might do it in an inconvenient way. Let's say you have 960 GB SSD. Choosing automatic partitioning might allocate only 25 GB for system, and the rest (900 GB) for home partition. And it's very frustrating, because apps install (using sudo apt install 'app') in system partition, not home. So always use manual partitioning and put a lot of size for system (/). It can be intimidating, but you find tutorials online.

That's all I can think of. Enjoy your journey in Linux world!

Mint, Trisquel. I couldn't run a software on Zorin (aldebaran choregraphe), I tried to solve it but unsuccesfully. So I had to change the distro. I chose Mint. Very friendly. Than switched to Trisquel because it's 100% free and recommended by FSF. But for someone who doesn't care about Free philosophy, I recommend Mint.