can u trace?

That depends on the circumstances. Many view an intact hymen as evidence of virginity, but it is not proof. A slack vagina would possibly raise questions.

Why do you ask? What particularly do you have in mind?

just want to know if a girl is intimated boy will comes to know a girl is not virgin?

That depends how intimate you get. If a boy examines your vagina with a view to finding out whether you have an intact hymen, he could decide that its absence means you are not a virgin. If he feels inside you, he might think you not tight enough. But if he puts his penis inside your vagina, he will know you are then no longer a virgin, and would possibly tell others.
What sort of intimacy have you in mind?
You must decide beforehand what your sexual boundaries are, and keep to them.
Hope this helps