Characters in One Piece. Do they Age?

Character Ages in One Piece...

I have some of the ages of characters from "One Piece" Taken from SBS "(Shitsumon wo Boshū Suru, "I'm Taking Questions") is a question-and-answer column that began in volume 4 of the manga, in which Eiichiro Oda answers questions sent in by his fans, making jokes and sometimes telling useful information about the story and characters.''

He was asked in different questions about different Characters and here are his answers:

• Luffy is 17
• Zoro is 19
• Nami is 18
• Usopp is 17 
• Sanji is 19

He has also given the Age and Height of the some of the Shichibukai:




Moriah: 48 years, 692 cm
Kuma: 45 years, 689 cm
Teach: 38 years, 344 cm
Doflamingo: 39 years, 305 cm
Jinbe: 44 years, 301 cm
Crocodile: 44 years, 253 cm
Mihawk: 41 years, 198 cm
Hancock: 29 years, 191 cm


 But there is one thing that makes me more Curious Because when he was asked about Shanks Age he said:

• Shanks I'll tell you his age from 10 years ago. He was 27 at the time he was hanging out in Luffy's village. 

I think there are 2 Theories about this, Either Shanks wont age so i means he is still 27 or no one in the One Piece wont age, what is probably not true.  Or maybe he was just trolling what do you think???