PLEASE HELP... If I already git init a parent folder, do I need to git init every new project I created in sub folders?

It depends on what you wanna do. Running git init tells git "everything in this folder and all its subfolders constitute a single project I wanna track". If you have a project in home/python/myapp and another one in home/python/anotherapp, it'd make sense to git init in both of those directories because they're both their own distinct project. You could also have a git repository in home/python that will also track both of those projects in one repository, but that doesn't really make much sense to do imo. All in all, a git repository is meant to track a single project at a time, so wherever you have the root of a project on your system, that's where you should run git init