So, an argument I have seen argue against credobaptism in the Bible is that infant baptism proponents will say "Of course there's no evidence of infants being baptized in the Bible. That's because the first Christians were converts, and you can't build the Church without converts first, so there were no infants to baptize at the time. It was only after those concerts started having kids and raising them in the Church that infant baptism emerged."
Idk if I'm doing the argument justice, but I think that's the gist of it. What would you say in response?