What is the best screen size to start wireframing with?

I'm new to mobile app design and I'm looking for some help.

I saw a number of screen sizes available in Adobe XD but I don't know which one is the best to start designing with.

I've heard someone saying that it's better to start with the smallest screen size because it's more compatible when scaling-up to bigger screens.

I'm wondering that is true or not. Is it better to start designing for smaller screens first?