Congratulations. You are more normal than your friends, according to my FIL the biochemist. Your body really does 'tune out' the scents of your body unless they are (1)fresh, or (2) very strong. I'm exactly the same way and have actually cut out of my life everything that has a scent (my daughter's skin reacts to many dyes and perfumes). Makes it much easier to notice other people's perfumes, but I get easily overwhelmed in a crowd. Since it's a normal reaction, I think the only thing you need to worry about is your nose getting so used to a scent that you can't smell it anymore, so you put on a double dose, and then gradually a triple dose, and so on until you are literally bathing in the stuff.