I'm 18 and off to uni very soon too, and I've been thinking about the effect it might have. But I think this thinking is the problem! I'm forcing myself to try to realise that it's not a problem! It's easier said than done, but I think making a conscious effort to avoid word substitution is a starting point. I'm telling myself to accept it, and appreciate the fact that I've not got anything worse than a moderate stutter, which - in the grand scheme of things - is absolutely nothing. Hopefully some day will come when it clicks and I actually think "I don't give a shit about this anymore!". Doesn't really matter anyway since, there's no way to avoid it at university. It'll be a baptism of fire regarding public speaking. Anyway, enjoy college wherever you're going!