“I may not have been my mother’s favorite child, but I was the first one she thought of whenever the police turned up” is the English equivalent of the Vietnamese phrase. If you’d like me to translate it to Vietnamese, please let me know.
As for “Shirt,” I’m assuming that’s meant to be a reference to a piece of clothing? If so, the complete phrase in English would be:
“I may not have been my mother’s favorite child, but I was the first one she thought of whenever the police turned up shirt.”
This suggests that the speaker may have had a bit of a troublemaking past and that their mother was protective of them, even if they weren’t her favorite. The shirt part may refer to a shirt that the speaker wears as a reminder of their mother’s love and protection.