Is Covilha safe for solo female travelers?

Covilhã is small city that's why the most of people know eachather. I'm living here as an Erasmus student and I can say that its student city because the students are more than locals I guess. The most of time people between 18-35 are partying untill late hours and its feel safe for me cause there is still people are outside even it's a small city. I'm studying at the night at the centeral library which is open 24/7 and I'm going back to home sometimes at 4am and sometimes there is still students are at outside. The only thing that make me nervous, there is a homeless guy all the time at outside and talking with himself and sometimes with the people around and he seems high all the time or he is have same hallucination or delusion. But I don't think like this guy gonna hurt someone. In my experiences Covilhã is safe place to visit but it's small city there is not tahat much thing to visit besides the nature✨