Welcome to the world of do what you feel like when you like! Living alone is incredible!
Get your locks changed. Give a spare set to a neighbour you trust or whomever. Sliding windows? I put dowel in them so they only open when dowel out. It’s round dowel so spins in track as square easily lifted. Switch to electronic mail so letters get less for important stuff. Cat alarm is better than dog alarm if can. Baseball bat under bed/behind door. This is optional. I never have, but did when lived in van. Get to know your neighbours, as many as can. Local shop people and postie/bin people. Safety in familiarity. Need a person? Handyman or something? Get one neighbours use. Familiarity is safety.
Best of luck. Spend heaps of plants!