I think she is not 19 yet, assuming her age was 8 or 9 back then so now she is 16 years old
She might be the same age as Senku before he was petrified. 17 years old perhaps?
I thought so too but apparently she was first introduced at 9 but before they all got petrified Suika was 12 so now she's 19. Its even on the wiki
I wanted it to be so, that she was at least 16 but the wiki says she was 12 before she was petrified so now she's 19.
I really didn't want such a big time skip to happen because Ryusui is such a big brother figure to Suika & I definitely don't want her to be shipped with any of the adults even if she is 19 now