For Ashkenazi Jews it is the Haftarah of Parshat Beshalach. This Haftarah has 52 verses (Judges 4:4 to 5:31).

The HafTorot come from the Nevi'im (Prophets) section of the Tanach.

Religious Jews don't call it that. We have a Bar Mitzva at 13 years old, when the young man reads a Torah portion or Haftarah (portion from the prophets).

No, As a bat mitzvah myself I only had 7 months before the date. I did blessings, three aliyas, and a whole haftarah.

Also known as a bimah, they are raised platforms in the center of the synagogue with a raised reading desk, where the Ashkenazi (German) ritual, the Torah, and the Haftarah are read during Sabbath and festivals.