The Effects of Aging

So we know Ranma turns into this cute red-headed pig-tailed girl when dumped with cold water. I wonder, how aging would affect this transformation. Would the transformation of the girl also age with Ranma's physical age, or since the Red-head drowned when she was 15, would that form forever remain as a 15 year old girl?

Apparently in the manga there is someone that fell into a spring of drowned child that reduced them to a younger form that aged? So it probably would age with Ranma too. Even if you ignore that, the cursed transformations usually incorporate elements from their normal form and not being a one to one of the animal. Like I doubt the cat Shampoo takes after happened to have her hairstyle. So it is possible the templates mix with the original on being cursed. Which in that case, makes sense they would age at the same rate.