no, but you'd wanna back up your world anyway
No, as long as you get it from the official website minecraft.net. BUT if you start installing mods there is a chance they could be a virus. So always get your mods from credited sources.
You may be installing them wrong, or may not have the right version of mod. There is also a chance you are installing conflicting mods.
force update minecraft to clear all your mods then if you want try again.
you can get minecraft mods and textures off the minecraft mods website.
After downloading and installing Forge, you can download mods from websites like CurseForge or Modrinth. Once you've downloaded a mod (usually a .jar file), place it in the "mods" folder located in your Minecraft directory (typically under .minecraft). Launch Minecraft using the Forge profile, and the mods should automatically load. Make sure the mods are compatible with your version of Minecraft and Forge.
Mods do work on Windows 8 laptops, you just most likely aren't installing them correctly
Yes it can be depending on how many mods you have installed and how much RAM you have
With mods yes however with just vanilla minecraft no.
bearshare is not required to get minecraft mods.
there are no mods in minecraft pe i hope there will be
Yes, most Minecraft Mods are updatable.
Go to start menu, type in %appdata%, if there is ".minecraft" when you search, then you can. Anyways, why using demo?