YOU SAID:

He looks weird especially for a 10-year-old

INTO JAPANESE

彼は特に10歳の人にとっては奇妙に見えます

BACK INTO ENGLISH

He looks strange, especially to a 10 year old

INTO JAPANESE

彼は特に10歳には奇妙に見えます

BACK INTO ENGLISH

He looks strange, especially at the age of 10

INTO JAPANESE

彼は特に10歳で奇妙に見えます

BACK INTO ENGLISH

He looks strange, especially at the age of 10