This is one of the Adinkra Symbols denoting different concepts or aphorisms.
It is called WAWA ABA, seed of the wawa tree. It is a symbol of hardiness, toughness and perseverance.
From above linked page,
The seed of the wawa tree is extremely hard. In Akan culture, it is a symbol of someone who is strong and tough. It inspires the individual to persevere through hardship.
This might depict virtues of Shuri who is strong, brave and intelligent which we have seen in the movie.
From this interview with Ruth Carter (costume designer),
I have to ask about the details. I noticed the adinkra symbol, which I believe means "cooperation,” stamped across W'Kabi's (played by Daniel Kaluuya) blanket and other symbols in the movie. How did you come up with that, and who would wear what?
Ah! You caught that. Very good! Yes, there was a Ghanaian Adinkra symbol on W'Kabi's blanket, as well as on Shuri's blouse when you first see her in the film. There are symbols everywhere, actually. T'challa also wears a different symbol in his throne room, Killmonger's mask is a dogon piece, and N'kiya and her father of course has the most prominent traditional symbol with his lip plate.