The opposite can also be true. Futaba Anzu is 17 but is usually always drawn in a very childlike manner. So, here, she's often tagged as "loli".

I don't know the story or lore behind Neptunia, so I don't know why Ram and Rom look so different between their forms, but their pink and bluish forms don't come across as loli to me in any of the posts I looked over.