Would you consider this a sin if I tried this?

You have to admit that there are people in the world who are extremely intuitive. (eg. Psych Twins Linda and Terry) I'm not claiming to be psychic or anything but I do have this ability to read people (their body language, their mood, and other simple things). Most of the time I am right. Anyways, as a career I'm thinking of becoming a clinical psychologist. I really wanted to buy/read the Psychic Twin's book: Psychic Intelligence. I don't want to be a healer or anything or tell people's futures. I just want to heighten my intuition a little. This has nothing to do with my question but is it also a sin to believe in past lives? Thanks! - Allie.