Aisa bilkul bhi nishchit nahi hai bete ki pehli baar finger karne se ya sex karne se blood ayega hi. aur yes aisa ho sakta hai ki finger ke duran hymen break ho jaye. zara is hymen se judde apnay doubts yeh padh kar clear kijiye. http://lovematters.in/hi/resource/faqs-hymen-and-virginity