AITA for wanting the door locked?

My roommate and I live in a not-so-great neighborhood in a major US city. There’s a lot of drug activity nearby, unhoused people around, and overall it’s not the safest area. We’re two young women living alone in an apartment. The issue is that my roommate constantly forgets to lock the door. I’ve reminded her many times, and she even put a sticky note on the door for herself, but she still forgets. I work as a bartender in a strip club and I keep a lot of my income in cash. I also deal with some questionable customers, and while no one has followed me home yet, it’s a genuine fear. Meanwhile, my roommate works from home and says she doesn’t feel unsafe with the door unlocked.

What bothers me even more is that every time her boyfriend is over (who is rude to me, by the way), the chances of the door being left unlocked are even higher. When I bring it up, she gets annoyed, as if I enjoy nagging her. I really don’t, I just want to feel safe in my own home.

She told me that if I need the door locked to feel safe, then we should split the cost of an automatic lock. I agreed at first and let her choose the model, which she bought for $140. But now I’m starting to feel resentful about having to pay for half when locking the door is such a basic responsibility. After a big argument about it, she said she’d cover the cost herself but doesn’t want to talk about the situation anymore. We used to be friends, but at this point I’m not sure things can go back to normal. AITA for wanting the door locked?