As Iguana said, they're born with blue tongues that typically start to change to pink when they're between 6-12 months old. There is variation present in though, some start the switch earlier, others never undergo the switch. My pair are apart of the later group, both are still rocking blue tongues even though they're 5 years old.
Nice looking pink tongues kankryb, I bet you're happy with them.
Cheers, Cameron