According to your terminal display:-
1. You login as user IT (needs two tries at password)
2. You then su - and enter the password for root.
3. You then su - student
You don't need to login as users who you don't use...
For example, if I was already logged in, I could do the following:-
jeremy@hector:~$ su -
Password: (my root password was entered)
Basically, why not just login as student?