Non-porous hair just means that your cuticle layers are strong and are intact. It's a good thing!
It means your cuticle layers have not been exposed to much trauma or damage. Your hair should hold on to internal moisture much more easily, than someone with porous hair. Non-porous hair also has a hard time accepting chemical treatments like relaxers and colors because the cuticle is so compact/closed. So if you were wanting to relax or color your hair, that's the only time you'd really run into problems with non-porous hair.
Now, porous hair, on the other hand, is usually damaged hair. The cuticles aren't in good shape and they are either lifted, chipped, or worn. Porous hair doesn't hold onto internal moisture very well, and feels chronically swollen/puffy/dry. Protein helps correct this by reinforcing the cuticle layers temporarily. This fills in the cracks, helps lay down the cuticle scales, helps keep in moisture, and improves porosity along the cuticle. Porous hair EASILY accepts chemical treatments and tends to process very fast because of this.
Our hair is usually more porous as you travel down the length toward the ends. HTH. Be happy for your non-porous hair girl! The porous club isn't fun at all.