First time in a long time! If I use the Main Theme (VillaVista) change all the images and text in Editor, will I lose it all if they update their Theme?

Hi, It's been almost 15 years since I opened up wordpress and started from scratch.
My last time, I know I used a Child-theme, but for now I am starting from scratch and taking the VillaVista theme and editing all the images and text to reflect my info.
If VillaVista updates their theme, will it overwrite all of my info and potentially lose everything?
I forget how this works.