Q: Some texts write about reincarnation/rebirth but if it were true why does not every person talk about previous birth?

A: You – the pure awareness – have forgotten your true nature. You keep on identifying with thoughts and things that you are not. At certain instant you become a thought x, another instant you become another thought y and this keeps on going. This can be thought of as taking new birth every time there is identification with something new. Once false identification stops, there is no more rebirth. Not identifying means simply witnessing or there is a distance between you and your thoughts (Saakshi Chaitanya in Vedanta terminology).