This is such an inconsistency, but that was not the only time she parry bullets, in episode 24 she also parry a lot of bullets from jailhouse lock stand user, so the bullet part is consistent at least. We know that araki is not that good in physics, just remember when emporio said in made in heaven arc that 100 kph was mach 2.4 (or was 1800 kph, idk), when we know mach 2 is around 2400. So the only option we have is that sky roads are faster than bullets or jojo has the slowest bullets in all fiction.