I’m also a young woman that lives alone - I actually ended up buying these little magnetic door alarms that you can “arm” just by moving a switch on the device; if a door (or window, wherever you set it up) opens while it’s armed, it blares an ungodly loud alarm that could truly wake the dead. I set it every night before I go to bed and it offers me a huge amount of comfort knowing that if someone DID try something, my entire apartment building would be wake up 😅