Braided hair has been carried through the centuries by the most countries and cultures. From function to fashion the art of braiding is still alive to this day. You can read more about the significance of braids throughout history here
In Old Slavic tradition, a 3-part braid is a representation of 3 worlds: the world of dead, the world of living, and the world of the Gods; as well as the past, present, and future. A braid then serves as an antenna tuned in to all three of the worlds. Etymologically, the Russian word "kosa" (braid) shares its root with the word "kosmos" (cosmos), which becomes an additional suggestion of the esoteric meaning of the traditional braid.
Roza learned to braid from her mother and is interested in passing her skill along by sharing it with others on various occasions.