You size is not as per age , especially 11 to 12 am not able to share photos .the sleeves are small, and shoulders are shillinged
I have 3 sons mashallah
6 yers 1st one he his size as per yours size is 7 to 8
2 one 8 years old his size as per your brand 9 to 10
3rd one 11 years his size is not available at your brand ,