She does not choose to lead the people of Israel to battle but is told to do so. She goes obediently when told, but tells Barak that he will be shamed in that a woman will kill his enemy Sisera. It is also a shame to Barak that he cannot go to battle without a woman. As a prophetess, she speaks, but she purposely keeps herself in her proper position as a female by maintaining the safeguards of her husband's headship and obedience to the authority of Barak. It is also a shame to Israel that there were no men who could judge them and so God was forced to use a female.
Females prophesying is different from females teaching and exerting authority over men.
Females can of course prophesy with their heads covered, signifying submission and acceptance of God's ordination. Just as Deborah did. A man had four virgin daughters who prophesied. Same as above. See also 1 Cor.