Since one of the classes I teach is AutoCAD I get asked about this a lot. Yes after 3 years if you still have a valid school email you can upgrade too the newest version, I like to upgrade every year just to keep up to date with changes in the program.
One thing that is not too well known is this applies to all Autodesk products, I currently have Inventor on both my computer at work, and my system at home. But you can get copies of all of their products including Fusion, Revit(used in architectural drafting) 3DS(used in video games and movies) and everything else on their catalog.
Just remember that you need an educational email address, they do check up on this periodically and you don't want your program locked out in the middle of a big project.
That sounds great till you have to write it all into G&M code, that is one of the biggest advantages about using AutoCAD or solidworks, depending on what software suite you have some of them will write your programs for you like Catia will or you can dump your 3d model generated from solidworks or AutoCAD into something like surfcam and have that program write the code for you.