My parents forced me to do 3U Maths and 3U English on the basics that I could always drop it, so I did, and now both have grown on me (I'm keeping both). They said I had to do it because they had never forced anything on me ever in my life (which is very true), so this was the one time I should make a compromise. So I did. It was the best thing that ever happened to me.
So what's the situation with your parents? Do they let you do whatever you want, just like I did? If they did, maybe a compromise is a good idea, just for once? (believe me, I was really angry at them for a few days both before and after the subject selection form was handed in, but as I said, it was the best thing I ever did). If not, just stick with 3U Maths for a term or something and just see how it goes.
And how correct are your parents? My parents don't know much about the scaling system, the UAI or the HSC when it came to choosing my Yr 11 subjects, but they guaranteed me I would come to eventually like them, it was just a matter of time. My parents are always correct in what they say (it's the truth, it's not defending my parents or anything), so my gut instinct just told me to go along with it, and guess what? It turned out correctly.
Let us know how you go, yeah?