Hello talisca17,
Here's my suggestion.
In my opinion, your answer still cannot convince me enough. You need to elaborate more on 'why you want to attend this school.' Try to be as specific, rather than be broad.
I did feel that some of your sentences do not strengthen your answer, for example,
After IGCSE, I planned to study in Sydney, Australia for a foundation programme. Unfortunately, I had to turn down the acceptance offer because of financial reasons. Senior year comes, and my goal is still up there.
And, the final thing is you should pay more attention to grammar. Some of your sentences can be combined and more concise.
Hope this help :)