Hsc private exam without SC or GCE? ANYONE HELP

Hi sorry i asked the same question twice as i checked 'Best Answer'by accident!!

Okay so my question is can i do my HSC Cambridge exam private without SC or GCE..I'm 18 now just completed 4 form twice-Once in Ireland and Once in Mauritius.. I want to know if i could do my upper and lower in a year with tution?? Is this possible. Everyone in my family are saying do the GCE or SC? I really don't want to as the school course will take 3+years and a lot of money!! And i don't want to continue my (sc or gce) school i'm not adapting to it!!! HELP