Go for it. I planted an acorn in a pot about 10 years ago and it has developed a nice trunk about 2 1/2 inches in diameter, and a nice taper to a height of about 10 inches. The tap root isn't a problem, cut it off at the first repotting, and contrary to popular belief they do spread out feeder roots. This is an English Oak - Quercus Robur, and I am growing it in Queensland Australia, where our temperatures never get anywhere near zero during the winter months. So, if oaks can grow here, they can grow anywhere. As per the post from Inez, they do take quite a while to grow. The leaves DO reduce in size - mine are approx 1/3 full size at the moment but I expect them to reduce even more in the future. Being new to Bonsai, it may help if you get yourself some easier and quicker growing trees to work on while you wait for the Oak to develope. Have fun - I do
TinanaTaffy