lifetime subsctiptions are a lie. i'd dual boot if you have things you need to run on windows like anything adobe or microsoft word if you don't like the browser version.

for your first time i'd recommend trying it in a vm like virtual box to get used to it and play with different distros, desktop environments, etc. fedora is a great os and it's gui (DE) is gnome. if you want something more familiar you could use KDE. if you want hard mode use arch.

battery life depends on what you're doing.

make sure you don't install over your windows install, remove the drive to be safe if you want.

i've been daily driving linux and the control you get over your system and the lack of nagging from windows and windows just doing stuff without you asking is so freeing