system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] What will Shazam/Captain Marvel look like when Billy gets older?

His Shazam form is like a buff version of him grown up. What happens when he actually grows up? Is he just going to turn into a buff version of himself? 

What about when he's an old man? Will he always turn into a 20 something? Or will he start looking like that Merlin dude? Is he immortal?
gpt
His Shazam form is him in his perfect state no matter the age so it'll always look the same. If he stays in this form he will live indefinitely just like Black Adam who is hundreds of years old but looks like he's in his thirties.