Almost nothing about Mirabai can be established. She appears in no contemporary record, the dates given for her vary by decades, the identity of her husband is disputed among candidates in the Mewar line, and the earliest datable references to her come from well after the period she is placed in. The most detailed traditional accounts are hagiographies written a century or more later.
The songs are in the same position. They circulate in Braj, in Rajasthani, in Gujarati and in mixed literary dialects, in manuscripts and far more in oral performance, and the number attributed to her multiplied steadily over four centuries. Composing in the voice of a saint and signing with the saint's name was an accepted practice rather than a forgery, so what exists is a tradition of Mira songs rather than an author's collected works, and scholars have not been able to isolate a securely original core.
That does not make her unimportant; it changes what she is important as. She is the figure through whom the devotional traditions of northern and western India carried a woman's refusal of marriage and of caste sociability, and gave it religious authority. Her modern reception has kept doing the same work, in films, in the concert repertoire of Indian classical singers, and in feminist readings that take the songs as the earliest sustained female first person voice in the region's literature.