Hi,
It would be a pleasure to be part of your team & helping you test you site. I would check your website security fails, broken links, 404 errors, bugs, speed, usability, functionality, checkout page, responsive, mobile navigation, missing alt attributes, missing titles, image size & everything that could affect or be affecting your site security, usability & search engine.
I have a master degree on ecommerce, that will be useful.
Best of Lucks
Elisa Lubisco