Parks wasn't the first instance of a black woman standing up to segregation laws. Claudette Colvin was arrested 9 months earlier for refusing to give up her seat to a white woman on a bus in Montgomery, Alabama.

https://www.msnbc.com/opinion/claudette-colvin-who-refused-budge-rosa-parks-did-finally-gets-n1286255

From Wikipedia:

Colvin did not receive the same attention as Parks for a number of reasons: she did not have "good hair", she was not fair-skinned, she was a teenager, she was pregnant. The leaders in the Civil Rights Movement tried to keep up appearances and make the "most appealing" protesters the most seen.