We live in a capitalist society where the most visible measure of a person's worth is their contribution to the national GDP.
That said, in my corperate and governmental endeavours, I have contributed more to the GDP than every 21 year old I know combined. I am on track to buy a house before I am legally allowed to drink. I already own my own car and am a completley self supportive, contributing, mature member of our society. I am on the cusp of graduating with my 4 year CS degree in 2 years 9 months from day 1.
People who would discriminate me because of my age (car rental companies, and the LCB) can go to fvcking hell. When I'm done working my 50 hour week that keeps the damn LCB's inventory system functional, they owe me the RIGHT to purchace my own beer.