So i have to variables that i cant seem to work together to hide it correctly

[Is the Student Under the age of 18?] = TRUE, AND(ISBLANK([Custodial Agreement File Attachment]) = TRUE)

This seems to only account for the first one and always shows it if true. But I wan’t to hide it if another field is also True in the same field. But i cant seem to figure out what im missing can anyone help?