Medical Testing / Interview
When it comes to the Medical test, those are standards applied by the Canadian Armed Forces and are subject to change. If you are fit and without injury your application will likely be accepted, but this is entirely up to the discretion of the Canadian Armed Forces.
As far as the interview goes, that is also up to the Canadian Armed Forces discretion. Although I would reach out to your school councilor or employment councilor for tips, or contact FSIN for help with interview tips.