Absolute soft shiny Straight hair turning wavy

Hey all!

I was born with super straight shiny soft hair, I had not oiled it well during pandemic and the place I moved to isn’t that humid too! Like it was still straight in Florida but when moved to Texas its become more rough, nothing changed in hair care routine except me stopping oiling hair. And then postpartum hit and my hair has started turning wavy. I don’t know if its heat styling/curling done bad or the hormones. Has anyone been in this situation before and what did you do?