As far as i know universities encourage int students to apply as early as possible. Seven months is not too early in fact. As per CIC website singapore visa office takes 10 weeks (2.5 months) to process study permit applications.
I would advise You to start with the process right away particularly if you are interested in arriving early, e.g. one months before yr course start date.
Good luck.
p.s. u can post the same question in the thread named 'Bangladeshi applicant?'. joining this thread will probably be helpful for u.