dont sacrifice your comfort on the bike for vanity. buy the shorter stem, ride with it for a while, and if you start to feel cramped, or the need to stretch out more, buy a 90. maybe sometime after you're a little better adjusted you can go to the 100, maybe not. maybe the frame is on the large side for you, and this short stem is what you need. either way, dont ride a longer stem and hope to "grow into it" - thats silly. buy what makes you comfortable NOW, or you're going to hate your bike.