Maybe. Ichigo thought she was about his age, that's why she got all pissed at him, and she passed for a student pretty easily.
Although that would mean that Shunsui and Ukitake are the equivalent of 100 years old. And Yamamoto is at least 200, so I dunno.
And Byakuya only seems to be in his early twenties (to me) in the current time, and he looks about thirteen or so in current time.
And Hitsugaya is, what, twelveish? And he hasn't really aged in 15 years, so it's probably a bit slower than a 10:1 ratio