Updated Windows steps for v1.0.2
1.) Delete the entire game folder titled "DatingStartVN-1.0.2-pc"
2.) Type in "%APPDATA%/RenPy" and press ENTER.
(Your appdata folder might be a hidden folder! You might have to show the hidden items/folders in order to find it.)
3.) Once in the folder, find folder "DatingStartVN-102" and delete it.
4.) Once that's done, you'll need to download/unzip a new copy of the game. :) Then you'll have a blank slate.