You need to assess whether you are capable of getting in to medicine. Medicine is one of if not the hardest degrees to get into. It is extremely competitive and many people fail to make it. With an ATAR of 70, its extremely extremely unlikely that you will be able to suddenly pull up your socks and cruise your way into a medical degree. I hate to be so negative and shoot down your dreams, but you need to be very realistic when considering this course. However, in saying that, feel free to prove me wrong.
1. repeat hsc, sit umat - takes a minimum of 1 year
2. do a BSc, sit gamsat - takes a minimum of 3 years
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but the question you have to ask yourself is whether you can get the marks required considering you got a mid 70s atar, there are no easy ways into med, for option 1. you'd need an atar of 95+ and a umat of 85+
anything is possible mate. you just gotta believe in urself.
but nah really. like OE said, u probably gotta finish a uni degree or repeat HSC.
1. finishing a uni degree and then doing postgrad med is 7 years minimum (3 year undergrad degree + 4 years grad med)
2. repeating HSC and getting into undergrad med is 6/7 years minimum (depending which med school you go to). this option is risky since if you dont get into undergrad med, you've just wasted a whole year.