I don’t know how you can check whether you’re getting concession (you might be able to go to the TransPerth info desk at the main train station and get them to check there), but if you’re a UWA student, I know how to register it to ensure that you are getting it.
You need to head over to StudentConnect. In the left-hand red banner, under “Profile”, there is a “SmartRider” option. You enter your SmartRider number into the little dialogue box, and UWA will sort it out with Transperth that your current card will be converted to a tertiary student card. If it already has the concession, then at least you’ve double-checked. If it didn’t have concession, congratulations, it now does :)