Your first financial year would be from 21.10.2013 to 31.03.2014. As per first proviso to section 96(1) of Companies Act 2013, in case of the first Annual General Meeting, it shall be held within a period of nine months from the date of closing of the first financial year of the company.
So due date of AGM in your case, would be 31.12.2014 i.e. within a period of nine months from the date of closing of the first financial year of the company.