Is having multiple rows of tabs against Material Design?

As seen in this mockup, I kind of need multiple rows of tabs.

One to click into categories, and another one to select your category.

Is this ok?

Also, side note—If Categories is selected, should I have a page where all the different categories are shown, then the user clicks on the one they want (as per https://rrrepo.co/explore) ? Or should we just automatically go into the first category?