It can be helpful to provide more context to accurately interpret what the guy means when he says "That a girl." However, generally it could be a positive remark acknowledging a girl's accomplishments or actions.
Atta is the word used in Hindi. its English translation means 'flour'
atta girl
It means twin in Akan language of Ghana.
Atta means millipede.
It means what's up :3
Atta = "That's a" or "That was a"
Gregory Atta was born in 1815.
Atta Kim was born in 1956.
Atta laevigata was created in 1860.
Atta colombica was created in 1844.
Atta - novel - was created in 1953.