Pretty cool but 2,000 years old Roman era encampment is not iron age.
No, Iron age is somewhat fluid concept.
In Americas, e.g., it never happed. The Natives lived in stone age until Europeans arrived.
Stone age persisted in Australia, Africa and e.g. Hawaii until Europeans arrived there too.
While Iron age officially ended in Mediterranean well before Trajan emperor, the Germanic Iron Age in Scandinavia actually lasted until AD 800.