Is becoming a lawyer a good idea? I'm really keen on studying law once I've finished high school, but I don't know if it's a good idea or not.

No one career is either good or bad for everyone. Whether a particular career is a good fit for you depends on your skills and interests. 

The first thing about becoming a lawyer is that it takes a long time. You would need to complete a four-year undergraduate degree followed by three years of law school. It can also be quite an expensive undertaking; many law schools can cost over $150,000 for a three-year program,...

No one career is either good or bad for everyone. Whether a particular career is a good fit for you depends on your skills and interests. 

The first thing about becoming a lawyer is that it takes a long time. You would need to complete a four-year undergraduate degree followed by three years of law school. It can also be quite an expensive undertaking; many law schools can cost over $150,000 for a three-year program, as you can see using a law school cost calculator. In general, admission to law school requires an undergraduate GPA of 3.8 or above and good scores on the LSAT exam. 

If you are a good student who enjoys analytical thinking, writing, and extensive reading, law might be a good career choice. However, it might be best to choose an undergraduate major that would prepare you for a broad range of careers, but which includes several courses in writing, oral communication, and logical reasoning, all essential skills for lawyers. Among the most highly recommended undergraduate majors for aspiring law students are history, English, politics, philosophy, and economics. 

As you are just finishing high school, you have a few years before you need to decide whether to apply to law school. A good strategy might be trying to find a summer internship at a law office to see what lawyers actually do during their work days so you can decide whether it is a career you would enjoy.