Parents hate my girlfriend...?

We're both 15. We were together since we were 13 (both scorpios, met in september) and have been going out for well over a year now...about a year and 3 month. Now, my girlfriend is the artsy type, and tends to manifest her feelings of affection in writing little notes and drawing little pictures for me. Now what happened is that this summer I went on a vacation with my dad, and my mom somehow found my stash of her little notes (there's an entire folder-ful, but ive done my best to hide it). Now, when she looked through it was the typical mushygushyloveydovey stuff, however some of them were more ual in nature, sketches of her on top of me making out...or me on top of her, her sitting on my lap, her licking my abs teasing...(which my mom interpreted as oral = =), but nothing worse, etc. Now, i find this perfectly natural for a 14 year old girl (with a high drive as well, and as ive said, she manifests her feelings in sketches and notes) as a way to express herself without hurting herself. Naturally, mom freaked out, and had a talk with me (more concerned rather than rage), and told me to tell her to stop. Things were going well for the next few months, however there were times when ive been on the phone with my gf all night, talking about stuff (life, movies,video games (yep she's better than me at some > >), etc.). This led to them taking away my phone... Now a few months later, they found another note, which was given to me in early september just when school started. This one was of me and her laying in a bed, presumably naked, as there's little piles of clothing on the floor, and I'm drawn as shirtless and her lying on top of me, but im covering her but its presumed she's shirtless as well, and the lower body is covered by a blanket, just cuddling in a bed without clothing.(yes, while it may be inappropriate, they don't really have a right to rummage through my stuff for evidence to "incriminate" my gf) Naturally, being asian parents, they completely went berserk. They thought that I was merely an object for her ual desires, that she was seducing me, gonna ruin my life and reputation, that she has no moral standing, no dignity, psychologically imbalanced, basically a slut, gonna accuse me of if she doesnt get what she wants. However, if she actually was, she wouldn't care about me and only use me to fulfill her desires. I've only been to first base, the worst being freaking at a school dance, and when she tries to go further when we're alone, i turn her down, both because of my own morals, and my christian beliefs. I've talked to her about it, and she also believes in the virtue of chastity, but that you should "have a little fun while you can", she understands that im not ready for some sorts of things, and she accepts me for who I am. If she was just some crazed teen, she woulda dumped me in the first place to find a more "inhibited" person, and I woulda done the same, because I wouldnt want a girlfriend that wants me for only . Also there might be some other reasons contributing to my parent's hatred... with the picture only being a valid reason to "scapegoat" her out... my grades have been fluctuating since i've entered sopre year (because of the obvious difficulty of keeping grades up), going from 4.0 to 4.17 to 4.3 but never being less than 4.0. My parents blame this on me "wasting my life" with my girlfriend. Her ex was actually my parent's friend's (also asian) son whom i've known since elementary school. It was a middle school relationship, they were secretly "dating", and she made this easter thing for him for easter with her artistic talents. His parents found out, and freaked out, finding out that he had been talking to her late at night (11:00ish). Having had a close relationship with my parents, his mom told mine that she was a bad person, no morals, etc, trying to steal her son away, distracting him from the oh so righteous path of education. My parents would have obviously been biased as a result of this incident. Another possibility would be a bias between different cultural regions of China that we come from. My parents are from Hong Kong (Canto), and her origin is from the mainland. My parents have biased stereotypes on how people from the mainland act, and this might contribute to their hatred... and again another possibility would be because I am their firstborn son. They had no experience whatsoever in dealing with a teenage son, let alone one with a girlfriend. She's my first girlfriend...and before you go saying "oh you should break up with her" or "oh she's not worth it", i feel she actually is. I've been infatuated with various people throughout my life, I even remember my kindergarten crush. I've been so obsessed with some people, that they were the only people I thought about for mont