As you knew we already wasted 6-7 years, some of us might be too old for couple more years of study. While under student visa you can't really get a proper job or earn enough to support your entire family living in Australia. It might bring great burden to your sponsor to prolong your stay and study.
Anyway, no doubt this is one of the alternative solution to move to Australia, but provided you still able to coupe with the study while working a part-time job, at your current age.