E-commerce is not a very time consuming course. You still have time to do more house renovations while studying. You are still young you can choose which way to go later.
I think if you’ve left school or worked fulltime for at least 2 years you can get Govt Study assistance to go back to study. You can check this with CentreLink.
It depends on personal circumstances. It would work well for me if I knew this option few years ago. I could make an IO advanced payment for my IP to reduce my taxable income for my last year at work. I could claim 48.5% on tax for the IO advanced payment & at the same time reduced my superanuation surcharge.