Seriously, any high school students who want to be a paralegal should start by looking at the job ads. What do the lawyers want? A paralegal is likely to do the work of not only a paralegal, but also a legal assistant, legal secretary, and receptionist. Although the legal training does not happen until college, there are several high school courses which would provide a good headstart.
First, an excellent typist. A slowpoke like me (45 wpm) is not the first choice of a lawyer who needs someone to type legal documents. Eighty wpm is better, and some can type well over a 100 wpm. Some lawyers absolutely want a transcriptionist! Shorthand is not as popular as it was some years ago, but is a skill which some lawyers want their office assistants to have.
Second, business machines! A 10 key machine might seem a little out of date, but many offices prefer someone who can operate one. Printers, copiers, fax machines, multi-line phone systems--some high schools allow students to work in the offices for practice. Proficiency with computer software programs, usually Microsoft, is important.
Third, paralegals answer phones, make presentations, greet clients, and sometimes represent their clients in court. Public speaking is a must.
Fourth, a lawyer's office also must consider accounts? Who will accept the fees, do payroll, pay bills, etc? Accounting is a preferred course, or some extra math courses, and some offices require knowledge of Quickbooks.
Fifth, a bi-lingual person has a definite advantage at any job. A foreign language is a big possibility.
Now, as I said, the legal training begins at college. If, after reading the previous posts, you should consider becoming a lawyer, be informed that getting accepted into law school requires a Bachelor's degree, letters of reference, good grades and an acceptable score on the LSAT. Good luck.