My mom's pregnant and told me not to tell anyone else. Not even other family members.
Why would she want to keep her pregnancy a secret?
She doesn't want to deal with their judgement.
It is normal to keep secrets sometimes but you shouldn't in a family. They will find out eventually and feel hurt not to know.
Blame my aunts, uncles, and cousins for being judgmental jerks.
Hiding this from the family doesn't solve the issue. Your mother needs to confront them about their judgmental attitude.