Hi Qihf
welcome to the Apple (user-to-user) Community!
Re: Age restriction issue with Apple ID on iPhone:
For some downloads, Apple requires a payment method is listed in your account, even if the app or game is free.
Also: some downloads / games etc. may be restricted for people your age.
Eg: It may be that parental controls for those under 13 are in place (on your device, or theirs) to keep you safe.
You may need to check with a parent or guardian, and find out if they may be able to assist.
You can also check how to: Manage App Store purchases, settings, and restrictions on iPhone - Apple Support
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Re: "because the iPhone says that message the game starts loading and doesn’t load and keep like this
because it is glitch ... please solve the issue and glitch"
We are all Apple users, just as you are, in the community ... so no-one here can access your account or details.
The error message you got seems to say it is your age restriction rather than a glitch.
It's that you can't sign in, that stops you. I could be wrong.
Feel free to let us know how you go, and if you (or a parent / guardian) needs more help.
All the best :-)