Are my kids too old to share the bathtub together?

Twins (b,g) will be 3yo in June, and my eldest son will be 8yo in April. For bath time I prepare the bathtub for all 3 of them at the same time and they love it and splash around, play together and it's not an issue for them BUT my husband thinks it's weird. He thinks the eldest is too old to share the bathtub with them but lets us do as we like. But it did get me wondering if it's time to stop... So...is it weird? I'd appreciate the input and I'll adjust, no problem. Thanks