Yourself
Whether you are a convert to Islam or were born into a Muslim family but have never covered, you must prepare yourself mentally for the way your life will change. This involves being thoroughly convinced that covering is a command from Allah, as well as knowing in your heart and being capable of explaining to others all of the benefits and logical reasons for wearing Hijab. Without this inner commitment, the outer appearance is meaningless. You must also be prepared to accept the added responsibility of being a visible representative of Islam, and therefore be on your best behaviour, being kind, fair, and polite and following all of Allah's injunctions. You can no longer mix with non-Muslim friends in Islamically disliked situations; no more riding the fence. If you want to be a Muslima but remain inconspicuous among the Kuffar (unbelievers), then you are not ready to cover.