Living in the same complex is not that big of a deal. What is a bigger deal is that you have made small talk with her twice while doing laundry and you think she is the girl of your dreams? That is a little frightening. And she would probably think it is a little crazy.
You don't want to come across as stalkerish, so just chill out a bit with her. If you happen to run into her again, during the course of your small talk, ask her if she wants to go get coffee or something. But don't make too big of a deal out of it. And definitely don't be upset if she says no. You are just a guy who lives close to her right now. She doesn't know you at all.
Good luck.
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