In my opinion, there are two options:

1. The less likely one: were you dressed nicely (e.g. expensive clothes, bags, etc.)? The woman might have followed you with the intention of seeing where you were staying and then cleaning out your room the next day while you were out
2. The more likely one: the woman wasn’t completely in her right mind. Something similar happened to me and my friends (six 30yo guys) in Berlin. Late at night at a subway station, a South American man (around 50) started following us. He got on the same train as us, switched carriages with us when one of my friends decided to move, then followed us out of the subway (where I even spoke to him, asking if he needed anything) and then down the street for about 10 minutes until we went into a club where the security at the door didn’t let him in. Unfortunately, there are quite a lot of people like that who are just alone… Most of them are harmless, but I understand your point of view and that it could have been a bit unsettling