Is it normal for a woman to invite you home to her when you are out late at night?

I am rarely outside past 9 PM, so I don't know how normal this is. What happened is that I decided to take a walk through the city one night, very late, around 3 AM. I was on the metro, and there was not a single person there except me for several stops, then a woman came in, not dressed like a hooker at all, just normal looking. Both of us were standing, I was looking at my phone, and she was minding her own business, not a word or a look between us. After exactly two stops, she slowly makes her way in front of me and asks me the question. I was left speechless for a few seconds before I responded with a silly "why?" and I won't expand on that conversation any further