Before you worry about the first paragraph, have you outlined or mapped out what the other paragraphs will include? It's pretty darned hard to introduce something you haven't written yet!!
DON'T start any paper's first draft by writing the introduction! How can you introduce a paper that you haven't written yet?
Follow the writing process, whether you're writing for science, history, English, or whatever:
Prewriting: Brainstorm, research, plan, outline, thesis statement
Writing: Write first draft by starting with section II of your outline; write the introduction after the body of the paper is written; write the conclusion last.
Polishing: Revise, concentrating first on the body of the paper, then the intro, then the concl (revision = making sure ideas are logical and sequential and support your thesis); proofread (spelling, grammar, usage, etc.)
Do you have a thesis yet? Have you done your brainstorming (and maybe research) yet? Have you written an outline?
Click on Step by Step for the process. Click on Info Search for help with researching.
Once you get all that done, here's an excellent webpage to help with actually writing your intro:
Thank you so much!