That's what I wondered too. The reason behind is during his debut, he looked very young originally, almost like a teenager. But originally the reason behind it was because he didn't have enough sunlight. Once he had enough sunlight, he swole up to an adult looking area and he was in the same age group as PG.
The key part though is that the question doesn't ask if Val Zod is going to be part of the young justice line up, it just says if Bendis has any plans for Val Zod.
So that could mean two possibilities.
1) He's taking Val Zod from the Earth 2 universe and importing him into the mainstream universe. In that route it will be very interesting how that would play since his father in Earth 1 universe is a stone cold killer.
2) He's using the young justice line to create his own val zod. But with young justice being about teenagers, this val zod would need to be de-aged to
fit within the line up.
The only reason why I see this leaning more towards option 1 vs option 2 is the introduction of Kon-El in Young Justice. The likelihood of Val Zod and Kon-El being on the same team is limited.