I live in Blacktown.
If its your lucky day (i.e. walk onto an express and walk onto a bus) it can take 55minutes.
Unfortunately you will be standing, and it is not usually your lucky day. If uni starts for you at 11am or later it will take you 1h 20min prob.
Getting to uni really late, 5pm or later can be murder. Once took me 2hrs....
Of course, these times are from when you GET to blacktown station ...
Ac