I posed this question to the Dev earlier this year and he concurred that over time the MC's rate of corruption would ramp up. She starts off from a very low threshold, having led an extremely sheltered life, much more so than the average person. So it stands to reason she's going to resist any attempts to get her to do lewd things initially, because of her parent's huge influence on everything she does. But now she's completely separated from that influence, and surrounded by people with completely different values, who are constantly pressurising her, to give in to her baser desires. And Lily is not a strong person. She did everything her parents told her to do. This has made her naturally submissive, and therefore extremely susceptible to corruptive influences, once that guiding parental influence has been eroded.