My sister is one of the managers at an aritzia. I can ask her about it. It is great that you are looking for a competivite job. I think that if you apply at any store that gives commission to their employees will be a bit more on the competitve side. i agree with all the other posts below. you should start looking and applying now for jobs. make sure you like that place and know what you want...

don't worry about your job experience.. volunteering is great. Hey you have to start somewhere right?