I had similar issues figuring my own hair properties. I think sometimes those of us with very thick hair have a hard time thinking of our hair as fine in texture. It didn't help that as a brunette, of course I could still see individual strands. I think porosity is just as challenging. I've heard the float test is unreliable, and the challenge with running your fingers up a stand of hair is recognizing the difference between a piece of hair that has bumps due to higher porosity vs bumps that could just be due to dryness, or just a strand that has some kinkiness to it's texture (even with fine hair, you'll still find individual strands that can be extremely different from most of the rest of your hair).
When I first started CG I believed my hair was medium-coarse, high porosity. Then I ended up over conditioned in less than a month. So I started adding protein and saw that my hair liked it, so I added more. Despite strong protein treatments and protein heavy conditioners, my hair never showed signs of being over proteined. I finally sent away for the hair analysis and found out that my "medium-coarse" hair was actually fine and my hair wasn't nearly as damaged as I thought- normal porosity and elasticity.
3a/f/iii Before the chop- Donated to Locks of Love, January 2013
Modified CG since 11/5/11
CO-WASH: VO5 Vanilla Mint Tea Clarifying, DevaCare No-Poo
CLARIFY: CHS Treatment Shampoo (used prior to PT/DT)
RO: DevaCare One Condition, Regis Olive Oil
LI: Cure Care, As I Am Leave-In
STYLE: Re:Coil, Curl Keeper, Biotera Gel, Deva Ultra Defining Gel, GVP Liquid Sculpting Gel, Curls Rock Amplifier and Strong Hold Mousse
PT/DT: IAGirl's PT, One n' Only Argan Hydrating Mask