My wife once told me that she inserted a pencil into herself when she was small, then when we eventually got married and had sex there was no blood, then now she tells me that the pencil she inserted then made her bleed. possible to bleed by pencil?

Yes. Children have been known to insert pencils and other foreign objects in both the anus and vagina as a form of self-exploration/self-sex. As they grow older and find the practice comforting/pleasurable they may change to even larger objects. The cultural expectation to bleed at first sex is outdated. Some women are born without an intact hymen or damage it is childhood.

Any hard object inserted or manipulated in or around genitalia can cause trauma and bleeding if intensity enough to disrupt mucosal integrity. Establishing trust and reconciling beliefs will be needed otherwise.