Revit 2018 officially came out today! Go to manage.autodesk.com or students.autodesk.com to download it; I was not able to confirm the student version is available yet!
Using Autodesk's Download Manager is the fastest way to get it... and, if the install is interrupted it will pickup where it left off when restarted.
Be sure to check out my annual AECbytes article to get a rundown on the new features in Revit 2018. There is a number of great new features!