Once i change from my pediatric endocrinologist to an adult one, could it be a good idea to have a neuroendocrinologist instead since more training?

Endocrinologist: Based on your profile, you have hypopituitarism. You need to be followed by an Endocrinologist. This is someone who trained in Internal Medicine and then Endo. They should have considerable experience in pituitary disorders, but you should ask whether they feel comfortable with this (some may specialize in diabetes only). You may also need to see an neurologist periodically.

It depends: It depends what your underlying condition is. As a doctor who treats both children and adults, I can tell you your age at 20 is a perfect time to transition from a pediatrician to an adult doctor, someone specialized in internal medicine and then had training in endocrinology. If you have a specific neuroendocrine diagnosis then someone specifically well-researched in that field could be of use.

Neuroendocrinology: You may need to see if your diagnosis has any Neurology need. If your problem is only related to Endocrinology you do not need a Neuroendocrinologist...

YES IF AVAILABLE: Yes it may e apropriarte in your case if you an find one in your area