How can I act like a confident woman as a shy person?

You don't have to be an outgoing or extroverted person to be confident. Try adjusting your nonverbal behaviors. Make sure you make good eye contact, hold your body with your shoulders pulled back, and have your torso aligned with the person you are either addressing or listening to. You don't have to speak constantly to be confident, or to exude it! But when you do have something to say on a topic, choose your moment and put your idea or thought across with carefully chosen words and with little regard for whether or not the other person will also see it your way. People notice the ideas of quiet people when they speak up and make a point.