Are babies adults in Heaven?

[SRoper]

Augustine suggested we would all be around 30.

I'll have to find that quote--it works really well on 30th birthday cards.

For even the world’s wisest men have fixed the bloom of youth at about the age of thirty; and when this period has been passed, the man begins to decline towards the defective and duller period of old age.

City of God xxii, ch. 15

That's the one! That's exactly the quote I've used on a birthday card. Unless I'm mistaken, in the wider context of the quote he speaks of the reasons why, perhaps, we will appear to be around 30 in our resurrected bodies. I don't have my copy of City of God handy to check, though.