Marco's Devil fruit and his actual age

What if Marco doesn't age because of his devil fruit ?

We already knew that one of abilities of Marco is Regeneration , maybe that also works on his looks / age.

It was shown in Whitebeard's past that both of them has almost the same age or maybe marco is just a little bit younger than Whitebeard but as what we had seen in the battle of the best in marineford , it looks like marco's looks doesn't change.

A captain and a first mate would likely be the same when it comes to age, so if Whitebeard is almost the same age as Roger then maybe Marco's age is also equal to Rayleigh .

In  greek mythology , a phoenix is a bird that can regenerate or reborn . the phoenix obtains new life through arising ashes of its predecessor .

I hope Oda Sensei will explain further regarding on marco's ability .