On the first day of Navratri, the Shailputri form of Maa Durga is worshiped and praised. On the first day of Navratri, Ghatasthapana of Maa Durga is done. Maa Shailputri is also known as Hemvati and Vrisharudha. Maa Shailputri rides a bull. Of the nine forms of Maa Durga that are worshiped during Navratri, the first form is that of Maa Shailputri. That is why Maa Shailputri is worshiped on the first day of Navratri.