Since I heard you now need a Microsoft and no Mojang account for Minecraft Java, I wanted to ask if that's true and if it's true, what age can you have such an account?
That's why I wanted to buy Minecraft Java soon
You don't need a Microsoft account!
Only brings problems. I only have one Mojang account myself and don't have to ask questions like "Why can't I play multiplayer because of Microsoft?"
Do not connect your Microsoft account to the Minecraft Launcher.
Yes, you need a Microsoft account for new Minecraft accounts. An exact age can't be found. However, the GDPR would have to apply. There the minimum age would be 16 years.
Without the consent of the parents, according to the GDPR, if personal data are required when creating an account, this limit does not apply with the consent of the parents.
Minecraft has USK approval from 6 years of age, children in Germany from 7 years of age have the opportunity to buy Minecraft in retail.
Accordingly, Microsoft is obliged to fulfill its obligation to provide services to children and young people, as was also possible with the previous Mojang accounts.
Whether Microsoft solves this problem through special children's accounts or through parental consent is up to them, but somehow they have to solve it.