Hello Balint Pataki,
This is a very good question.
I'm not a native speaker, but to me 'age' sounds as if it is here a part of the adjective phrase.
I've seen it several times in the same context, so I find it okay. I also think 'aged' has the same meaning as old, whereas 'age' focuses on the current number of years.
I hope this helps. Have a good day!