YOU SAID:
Today I turned 5 and I got a big cake
INTO JAPANESE
今日は5歳になって大きなケーキをもらいました
BACK INTO ENGLISH
I was 5 years old today and got a big cake
INTO JAPANESE
今日は5歳で大きなケーキをもらいました
BACK INTO ENGLISH
I got a big cake today at the age of 5
INTO JAPANESE
今日は5歳で大きなケーキをもらいました
BACK INTO ENGLISH
I got a big cake today at the age of 5
That didn't even make that much sense in English.