Dealing with my lack of comprehension

(Chapter 14 Comprehension Problems in my book)

Today I was talking to my Mom on the phone. I recently got a new mattress and box spring. My Mom asked me if my new mattress was firm. I went in my bedroom and pushed down on the mattress with my hand. Then I told her, “sorry, but I have no clue.” I guess I don't know what a firm mattress is supposed to feel like. She asked me if it was hard like her mattress and I said, “no”. I know that her mattress is extra firm which is too hard for me. I'm pretty sure that I usually know what the word firm means but today that just didn't happen for me.