Virginity is defined differently by different culture.Some culture gives more weightage to intact hymen. Some give importance to innocence of a girl and a boy.For legal point of vies, there can be difference in its defination. A doctor can say whether one has experienced intercourse.
What if a dildo goes insade the vagina?
Virginity is lost when you have sexual intercourse with a man. Putting fingers in your vagina is masterbation, a normal thing
The tip of a finger entering inside the vigina tells you nothing.