Is It Possible To Achieve Deeper Penetration Through The Cervix?

My girlfriend says she has an elastic hymen, that it runs in the family & is dangerous if forced to tear due to excessive bleeding. We have intercourse & I m about 6inches, is this even possible? With my fingers I can just reach a wall backing with a lump protruding towards my finger. I have normal hands & am wondering is this her so called hymen? Or is it more plausable that it s her cervix? Is it possible to achieve deeper penetration through the cervix; or is the wall I feel possibly the wall to her uterus?