Had you gotten to know her under the guise of this random-guy persona before asking a personal question? She may just be cautious about possible stalkers lurking about the net. It's remotely possible that she is not into guys at all. Homosexuality is the way of life for approximately 5-10% of the world population. Most likely it's the former, that she is wary of people that she doesn't know in person, especially if she's a shy girl. Like what 'kishi and MadHero said.