Why is my hair like this?

So I’ve been kinda confused on my hair type, i’ve always thought i just have straight hair. but lately i’ve noticed when i scrunch my hair to dry it after i shower, it starts getting pretty wavy. but the second i brush it it goes stick straight again. it gets wavy (ish) when it’s humid or as my hair starts getting dirty. sometimes some strands will become full curls. it’s not super crazy frizzy when it’s dry, unless it’s humid out. how do i test my hair type and know for sure if it’s wavy? or if im just crazy 😭 (edit after i showered, i feel slightly insane now, its not as wavy as i thought, but still figured id post and see what everyone thinks 🤷🏻‍♀️) ps, apologies for the super weird angles! 1st pic= hair after squeezing water out right when i got it wet. 2nd through 4th pic= after shower scrunching with towel. last pic is finger curled and letting it hang there for a little while.