There's many before her that had died in the name of Islam!
Its not Sumaya!
If you meant during the Prophet Muhammad
then it it to believe that
Sumaya bint Khayyat is first
but there was many before her for example:
Saidatina Masitah
The lady who combed Firaun's (Pharaoh) wife, Saidatina Masitah refused to worship Firaun unlike others Therefore Firaun ordered that all her family to be thrown in the hot boiling oil for disobeyed.