It's kind of hard to imagine.

Only if you go by launch date instead of laid down date (Akagi was laid down in 1920, while Sendai was laid down in 1922)

Sendai was launched in 1923, while Akagi was launched in 1925 (after Naka was launched). Sendai was commissioned in 1924, before Akagi was launched, while her two sister ships were commissions later in 1925. Akagi wasn't commissioned until 1927.

All the Kamikazi-class destroyers are also older than Akagi by launch date. The first three or four are older than Sendai.