To allow for friends to best search for you in the database, you should complete your profile as much as possible and your questionnaire in its entirety.
If your percentage of profile completion is not marked at 100% under your profile picture, this will NOT impact your ability to match with a roommate. The percentage completed indicates the number of fields that were filled in. It is common for students to leave fields blank, as they may not have information to share pertaining to the field.