You can either download Oracle 8i for buy a trial CD from www.oracle.com.
At present, knowing HTML and Javascript is not a big deal. Since you juts learnt these subject at school, I dare to say you just know some basics. Hope you try to know more advanced topics in these two subjects.
Choosing Oracle is a good decision. But you should be really competent in it. Visit www.oracle.com will give you more senses.
Anyway, you should first have an Oracle instance at home.