Would you say becoming a lawyer is "worth it"?

To start, I note I went to law school with Mitchel, the commenter above me, and I would reiterate everything he said. Some of my response may be repetitive, but it is likely valuable to hear it from multiple sources. In addition, I'd like to congratulate you on already considering whether becoming a lawyer is "worth it." Taking the time to start to formulate a plan now will save you a lot of time and effort in a few years whether or not you decide to go to law school.

My work as a lawyer, though still in its early stages, has paid off without a doubt. I am currently a term law clerk to a federal district judge (trial court), will be a term law clerk to a federal circuit judge (court of appeals) next year, and will be joining a large law firm as an associate the year after that. The goal / choice to work for judges before joining a law firm is not uncommon, but it is not the norm. I chose to do so because I knew I wanted to litigate, and my clerkships give me an excellent opportunity to learn from accomplished lawyers and hone my legal reasoning, research, and writing skills. While I'm only ~3 months into the job, I LOVE it. I get to do interesting work with people I like, and the time constraints are by no means oppressive (although it varies depending on the clerk / judge).

All the extra schooling was worth it for me. I had known since I was little that I wanted to be a lawyer, so law school was always in my plan. I knew I would like it, but I was shocked at how much I liked it. It can, of course, be stressful at times, but it is an intellectually stimulating environment, a (good) challenge, and, on a different note, a place where I met some of my closest friends. I love what I do now, but I often miss being a law student. It is true, though, that it is expensive. This is part of the reason it is so smart to start considering going to law school early, as it is a big commitment. I can say with certainty that I will not regret having to make a single payment on my loans, though. Also, many law schools offer great loan repayment programs and scholarships, so help is always out there.

I chose not to do a LSAT prep course. I did a little bit of internet research for tricks and tips, but mostly I just worked through good, old-fashioned LSAT prep books. As Mitchel said, the LSAT is totally within your control. It is a test of skills rather than knowledge, and, like any skill, with enough practice you will get better and better. I also enjoyed studying for it, as it was something totally different than what I was doing in college. Because I knew I was going to apply for law school, I started studying for the LSAT the summer after my sophomore year and took it during February of my junior year. I really intensified the studying over that winter break. Also as Mitchel said, though, the balance between the LSAT and your college classes is an important one to maintain (which is partly why I started studying so far in advance). If I had to do it again, I still would not take a prep course, as I knew I was committed enough to studying on my own. For those that need a little extra push, though, a prep course is a great way to "force" yourself to study. The one thing I would have changed, however, would be simulating the full LSAT more precisely (including the break during the middle). I just powered through all of the sections and then stopped, and I think more realistic timing could have benefited me.

As unfortunate as it may be, your college grades and LSAT score are probably the two most important factors in law school admissions. But you should definitely start cultivating relationships with professors who may one day write you a letter of recommendation, as those are still an important part of many applications, especially if a candidate is on the border between being admitted and being denied. Mitchel was also correct in that it does not matter what you study in college -- we went to law school with a piano performance major, a physics major, and everything else in between. I was a history major, and I think that helped prepare me for law school because I was already used to reading and writing a lot. Overall, take your studies seriously, and you should have no problem getting admitted.

I apologize for how long this comment is, but thank you for reading all the way to the end! I would also be happy to answer any more specific questions. Best of luck in the future!

Is becoming a lawyer worth it? If you decide to go forth with legal studies, you will get quite accustomed to the following answer: it depends. Most of the lawyers I know who are happy enjoy the job they are in and knew before they started law school that they wanted to actually practice law. So my first piece of advice would be to talk with as many people as possible who actually practice or have practiced law. If the day-to-day practice of law does not sound like what you want to do for a career, then you should probably not endure the trials of law school. That's not to say that a legal education has no benefit in and of itself, there is value in thinking like a lawyer (see http://jle.aals.org/home/vol63/iss2/5/) for an interesting take from one of my former professors). But, the costs are high and if you already know you don't actually want to practice (or teach) law then it is unlikely that it will be "worth it".
You are right, three more years of school is a lot. It is expensive, competitive, risky (job market is also hyper-competitive), and a lot of work. It can also be very enjoyable, intellectually stimulating, and a place that opens a lot of doors.
Personally, so far it has been worth it for me. But I am still in the early stages of my career. I knew I wanted to practice law and in the setting I am in. I was lucky enough to receive good advice about planning my career.
The first step facing you is the LSAT. I may be in the minority, but I loved the LSAT and studying for it. It is one of those standardized tests that can be mastered with practice. I spent a year preparing but only about 8 weeks full time. I was able to earn a scholarship for a prep course in addition to studying on my own. If you can do that, I would highly recommend it but otherwise, the prep course is not crucial. Most of the tips are available online and there are plenty of other resources available online. A course will help you stay focused and organized in your prep but, like anything else, there is a cost. The LSAT is the most critical component of a law school application and is largely within your control. Time spent preparing for the LSAT gives you the highest rate of return on your time when it comes to law school applications. I'm not saying to take time away from your classes at school, but build sufficient study time into your schedule.
As an aside, it does not matter what you major in! Study whatever you want. Law school is completely different and very few college courses can actually help you prepare for it so study what you want, get the best grades you can, and don't fret too much about taking "pre-law" classes if they don't actually interest you.
If you have more specific questions, I would be happy to answer more. But hopefully this gives you some things to think about!