Hello!
I'm EarthSci34 and I do 4-Units of English. However, I enjoy English Extension I the most out of all the english subjects I've undertaken (including creating my major work, which is still heaps fun btw)!
English Extension I is an exciting opportunity to see your limits as an English Student. What this essentially means is that you will be studying the VALUE of texts across a range of contexts, may it be historical, your texts as a classification or how it reflects the values of the time. In Year 11, you are free to study what the school decides (e.g. I did Gothicism, I know someone who did Utopias etc.) and will generally give you a feel of the higher levels of text interaction as compared to English Advanced. In Year 12, you study 1 elective, which is chosen by your teacher (or the school). These electives are Module A (Genre Study) Module B (Ways of Thinking) and Module C (Language and Values).
I do not necessarily agree with the post above. Referencing many of the other posts in BoS as well as my own personal experience, undertaking an EXTENSION subject is just as much work as a normal 2-u course. Consider this: you will be studying 3 texts IN DETAIL and then studying AT LEAST 2 related texts. Compound this with a detailed understanding of your module (with rigorous preparation for essay writing and creatives), it ultimately results with a challenging course that consumes much of your time. It is developing a personal understanding of your elective that defines the higher-end marks and allows your responses to be authentic and well-rounded.
I still highly recommend you try the course out. Although very demanding-- it is quite rewarding. You garner a new found appreciation of textual forms and features as well as increased insight into the significant value of texts. The workload can get intense, however if you do enjoy the additional challenges of english, then I would say go for it! Besides, you can always drop if you do not feel the subject as useful or too difficult. Also, EX2 is a possibility-- keeping your options open
I do hope my response has helped you with your subject selections. I do remember being hesitant to choose EX1 in year 10... but now I enjoy every minute of it! Best of luck with your confronting decision.