Oof, I hope not directly. Based on this evidence (also in An Elegant Puzzle) you wouldn't want more than 8-10 direct reports:
But you end up talking to all of them fairly often frankly cause any kind of drama / uncertainty gets delegated up pretty fast.
That said, if you are correct and it's direct reports - agree that's bad sign.
It would be a big step for a first management role, but not insane. The first time I did it got up to about that number in less than 3 months, so not day 1 but not far off it. This happened by having a regular sized (i.e half dozen) team first, and hiring another dozen person team soon after where it made sense to put them under my group.
The only reason we tried that is that a) things were going well and b) I had good mentorship in the role with the commitment of real help (i.e. time) from them if things started to get shaky.
I find it quite fascinating how this concept of moving into management is different from finance. There is still a lot of emphasis on actual doing here. Which makes sense in the "technical lead" sense of the title
e.g. It would never have occurred to me to include pair programming as part of management
Article also seems to imply a fairly flat organization. i.e. managing very few people / grades. By the time our guys get designated manager they've got 20 people reporting to them & have realistically been "managing" for years already.