No. It would complicate your application if you had been living with her before she got her PR, because if you had been living together 1. she would not have been eligible to be sponsored (maybe), and 2. she would not be able to sponsor you now. Someone who applies to immigrate to Canada, or is included as a dependent on the application of another, must declare their spouse or common-law partner. If they don't, they can't sponsor them later.
However, you weren't living with her before she got her PR, so this does not concern your case.
Since she was only 18 when she left, and presumably living with her parents, the visa officer will most likely believe you were not living together, though do make sure you include your addresses for that time.