It's fairly standard for AV agencies to make up (fake) profiles for their actresses, in the interest of protecting their (real) private information. AV agencies may sometimes let the models decide what stage name they want, but most of the time everything is decided for them.
Mainstream talent agencies (for fashion, singing, or basic gravure) may sometimes also change the model's birthday; but they will usually keep the same month and day, and change only the birth year.
In the case of Rina, there's not much info to hide since her entry into AV has already been clearly established. I would assume that her info from AKB is in fact the correct information, but that her AV agency was asked not to use any of the same information. Imagine if all the AKB48 fans in middle school googled for her profile and was immediately brought to her AV profile!
iripi:
