3 sciences is neither hard or easy, it is challenging. While I did not do any sciences I know through friends that it took a lot of their time tackling 3 sciences, particularly if the 3 were Bio, Chem and Physics. 2 of my friends dropped Physics who did that combination. My cousin is starting Year 11 this year and I along with her parents advised her to do Economics instead of Physics. She is doing Bio and Chem, Economics and Physics were on the same line. I told her that while economics is challenging, it would diversify her knowledge a bit more while also stimulating her analysis of issues that change constantly, unlike Sciences which tend to have the same content and not rely on current affairs (Earth and Environmental apparently been an exception). She took my advice and I don't think she would regret. While I don't know you, 3 Sciences is a specialization, and you have to ask yourself, are you set on what you want to do so early on in your education?