If this kids start buying Bitcoin at such a young age, they will be able to build and secure a bright future in their twenties.
I don't think it would be that easy for minors to buy bitcoin or crypto, especially when kyc is required by the more beginner friendly platforms that allow users to purchase crypto directly with fiat.
There may be p2p platforms where kyc isn't mandatory, but those can be considerably more technical and may require users to have a better understanding of how crypto transactions work. Some may be relatively user friendly, but that doesn't necessarily mean they are safe for someone who doesn't know what they're doing.
Before using any non-custodial or p2p method, you still need to understand how to verify the counterparty, avoid common scams, protect your funds, and make sure you're actually receiving the correct asset, etc. etc.. So while it's technically possible, it isn't necessarily as simple as creating an account on a mainstream exchange and buying bitcoin with fiat.
But yes, there might be some minors here doing stuff already, who already knows a lot on crypto and doing regular transactions already.