also to consider...

Don't know Canada tax laws, but US has some 'qualification' rules to tell you whether you are required to file tax return. These rules are specified in the form instructions or the publications for rules.

One common rule for US is the amount of money you earned during the year. The limit is low but since you said you only worked part-time in a fast food place, the amount you earned may be small enough that you are not required to file tax return that year. I suggest you find out what the rules were for that year for Canada's tax return. If the money you earned is indeed small enough that you don't HAVE TO file, you can use this as a reason to answer to the tax department.