Age verification for apple store

Hello Bikram_Sanish,

Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with verifying your age in the App Store. Try the steps here to see if they resolve teh issue: Update the birth date associated with your Apple ID - Apple Support

"Edit your birth date

If you need to change the birth date for someone below age 13, contact Apple Support.*

On the web

1. Sign in to appleid.apple.com.
2. Select Personal Information, then choose Birthday. 
3. Update your birth date and click Save.

Depending on how you created your Apple ID, you might be required to provide additional information or change your Apple ID username from a mobile phone number to an email address.

On your iPhone or iPad

1. Go to Settings, then tap your name.
2. Tap Personal Information. You might need to enter your Apple ID password.
3. Tap Change Birthday or Birthday. 
4. Update your birth date, then tap Done.

Change a birth date for a child

To change a birth date to any age below 13,* you must be a member of a Family Sharing group, and your family organizer must approve the change. After you change a birth date to any age below 13, you can't edit it.* 

1. Update the birth date.
2. Follow the onscreen steps to send an email request to your family organizer.
3. Your family organizer will get an email with instructions to approve the request. 

Learn more about Family Sharing.

*Age requirements vary by country or region. If you need to change the birth date for a child, contact Apple Support. "

We hope this helps.

Cheers!