But I can't find my save data file, how? Should I delete the game and start from the beginning again?
Save file location depends on your device of course. For example, on PC it's:
C:\Users\<User>\AppData\Roaming\RenPy\Harem Hotel
On Android I've heard at least two different locations, so you might wanna use your file manager and search for Harem Hotel.
Relax my dude, you don't need to start over simply because you haven't located your saves.