Typically, no.

Most people define virginity as vaginal intercourse, which would mean any other sexual practice, i.e. anal sex, oral sex, masturbation, etc. would not cause a woman to lose her virginity. However, some people/cultures believe that a woman has lost her virginity when she first makes sexual contact with another person. (This would mean that anal sex, oral sex, and masturbation, etc. WOULD cause a woman to lose her virginity.) Again, it depends on who you're asking.

So, NO, according to most people, fingering is not a way for a woman to lose her virginity.