I have been going grey since my early 20s, but it definitely started to spread like wildfire since my first pregnancy. Although I am now 34 so that could be part of it as well. It doesn't help that my hair grows ridiculously fast so I almost always have grey roots coming in, as if I didn't feel old already being pregnant in my mid thirties! My two older sisters don't have a single grey hair and neither of my parents started to go grey until well into their 50s, so not sure how I lucked out on this one!