She was born in 1282 as the first daughter of soldier Juan de Gomera, who got fame and land in reward for bravery at the Battle of Gomera near Osuna.

Her mother, Maria Ana, was one of maids of Fernando Núñez de Lara's wife, and she soon became in charge of her lady's wardrobe.

When Beatriz was still a child, Maria Ana taught her to tablet weave. Beatriz showed great talent for the technique. She soon became proficient in the craft to such a high level that her mother was not afraid to entrust her with the most expensive materials. It was because of this, and because of her mother's connections, that the young Beatriz found place among Elvira Fernández's maids. Thanks to her hard work and her experience with fabrics, clothing and weaving, she eventually worked her way up to become in charge of Elvira's wardrobe.

She managed her earnings well and started building up her own fortune.

Like any young girl from a good and wealthy family, she ended up stuck in a marriage. Her father arranged for her to marry Pablo Pérez, the eldest son of a rich merchant.

Their marriage wasn't a smooth one.

Although Pablo had promised that with such a beautiful woman by his side he would never turn to another, he was still notorious ladies' man.

Beatriz's younger brother, Juan, took the whole thing personally. He had several arguments with Pablo and protested against the wedding. After the marriage, father decided to send Juan away to Gomera.

The marriage indeed wasn't harmonious. When doña Elvira married don Rodrigo, Beatriz didn't hesitate to follow her lady to her new home. After the death of don Rodrigo, she tried to comfort the lady in her grief and followed her on her pilgrimage to Aachen.

When Doña Elvira decided to take refuge in the Kingdom of Bohemia, under the protection of her distant cousin Iñigo of the Haro family, Beatriz stood at her side.