If you were old enough to vote and you actually did vote in the federal election just prior, then that was part of your vote on the subject. MP's are sent to the House to introduce and vote on legislation in accordance with the policies they have presented to the electorate for approval during the election. Your other vote on the subject would have been your vote (if you cast one) for your provincial representative, as the majority of provinces representing the majority of Canadians had to agree to the Constitution before it could proceed. Again, it is an MLA's / MPP's job to introduce and vote on legislation. Referenda are NOT an appropriate mechanism for modifying the constitutional framework of a country.