If You can get an access to Solidworks i would very much recommend it (it's expensive, though). The possibilities are immense and although the learning curve may prove a bit steep for a complete 3D novice, it pays off later on. I don't know what do you plan to do in 3D printing, but in the future Your needs may extend further form laying plastic layers and then You need CAD drawings. That's especially true when you do some models of boats, planes or automobiles.