The simple present is used to make statements about events at a time later than now, when the statements are based on present facts, and when these facts are something fixed like a time-table, schedule, calendar. Education First
Firstly, What "when the statements are based on present facts" does mean?
Secondly, Is the following sentence follow the above rules? or isn't it grammatically correct?
I start my course at university next month.
or should I say:
I will start my course ...