The ArcGIS Online (AGO) cloud platform is being used in multiple courses, and important to support e.g. your ePortfolio, internship documentation and perhaps Master thesis. To keep your important work 'for posterity' after you graduate and to facilitate individual work outside of courses, it is recommended to set up a personal 'developer account', which will not expire and provide resources sufficient for most purposes:
Course instructors or coordinators / tutors will then be able to use this username to provide access to other ArcGIS Online content. This typically is done via AGO groups - in this case you will receive an invitation to join the group XXXX - when you login next, go to ‘Groups’ (top menu bar), there you can see the invitation – please accept it ;-) As an alternative, if the group name for the course is known, you search (top right corner) for the group XXXX (at left side, the checkbox ‘Only search in …’ has to be unchecked), and then request to be accepted into this group. Try this by applying to join group MAGI!
Of course it is ok to look around and explore the ArcGIS.com environment, you likely will use it a lot from now until your graduation! Anyone who cannot wait can get started right here: http://learn.arcgis.com/en/projects/get-started-with-arcgis-online/
Note: for some tasks, and in particular for downloading and licensing ArcGIS Pro and for taking online courses on the Esri Virtual Campus, you will need an additional account within the 'organisation' zgis.maps.arcgis.com. Content generated through ArcGIS Pro still can and shall be saved in your personal 'developer' account. This additional account will follow the schema of MAGI_firstname.lastname and can be requested by emailing Josef.Strobl@sbg.ac.at. It is advised, though, to keep any content items in your personal 'developer' account unless advised otherwise by a course instructor.