I don't think 1018 has enough carbon to harden properly. There's no point in going to all the work of grinding a blade if its not going to be usable when your done. You can get O1, 1095, 1084,5160 all for cheap, and end up with a very good knife.
Also, that size isn't really the best unless you plan on making big knives. I would recommend a blade in the 3" range for your first one, and 1/8" thick stock is plenty for that. Longer is harder to grind properly, and the heat treat gets more complicated too due to warping etc.