Is it easy for undergraduates to immigrate to Australia?

Your average grade of undergraduate course determines whether you can be admitted to a good university. But I don't want to throw cold water on you. If you want to continue clinical medicine, the chances are slim, because Australia has very strict medical requirements, and basically you have to interview. Some schools require you to take the OET, but at least IELTS 7.0.

If you still want to study medicine, you can transfer to other disciplines, such as physical physiotherapy, occupational physiotherapy or nutrition. However, it is also difficult to apply, and the number of places is limited. Generally, you need to apply one year in advance. IELTS is generally at 6.5. You don't need to go to OET. Now you should consult more intermediary companies, apply for conditional offer first and then prepare English.

You want to study medicine, and the school chose you, not you.