This isn’t legal advice, but the FTC probably won’t go after/ fine small creators (FTC wouldn’t have the resources). But YouTube, and their auto-bots however, may potentially mark your content as “made for kids”, and mess with your channel if you don’t mark videos correctly.
If your content is clearly targeted towards people under 13, you should probably mark it as such.
On the whole topic though (RANT INCOMING):
The stupid thing is creators can technically get fined now for “tracking kids” when we have no direct access to the data in question (emails, cookies, etc.). YouTube has all that exact information. And, according to the data YouTube does share with us, all the audience of our videos are over 13 (because you have to technically be over 13 to use YouTube).
But, YouTube went and promoted to advertisers that kids were watching their website, thereby admitting that they knew kids were on the platform. So the FTC could go then after them, despite the 13+ age gate.
In the settlement with the FTC, YouTube could have just marked the accounts that they knew where kids and not shown targeted ads to those viewers (and they knew which ones were kids, or how else would confidently promote that kids were using their platform to advertisers). Instead, YouTube took a $170m slap on the wrist and threw content creators under the bus. Ruining some entire channels (i.e. livelihoods), and making the platform even more difficult for independent creators.