I am a 20 year + attorney. I have no idea what any of the attorneys in my firm majored in for undergrad, and no one has ever asked me what I majored in. I really don't think your undergrad major matters, unless you want to be a patent lawyer (in which case a science or engineering major is an absolute requirement) or maybe tax law (in which accounting might be helpful, but is by no means a requirement). If you are sure you want to go to law school, major in whatever you think will allow you to earn the best GPA and LSAT score, plus help you with critical thinking, writing and public speaking skills. On the other hand, if law school is just something you are considering but aren't sure you'll actually do, you might want to choose a major that will make you marketable in some other field. Good luck!
My best friend from college had lost her dad late in her senior year of high school, and often spoke of how hard it was for her not to have him around to lean on and share things with as we went through our four years there together. Having seen her struggle with that, I really feel for you and am so sorry for your loss! I hope you find someone at school you can open up to about this, and don't hesitate to seek out professional counseling if you think you need it. You can probably find those services on campus and possibly even for free.
When my son started his sophomore year, I realized it was eventually going to be helpful to have a list of his ECs, community service, honors and awards, leadership positions, etc., so I thought back to his freshman year and wrote down everything I could remember he did. Then I started keeping a list of everything he did going forward, organized by year. Just a simple list (not resume format or anything like that) in a Word document on my work computer, but I put every little thing he did on there, when the activity occurred, approximately how long the activity took (e.g., twice a week for 3 hours each time between April and October) and what club the activity was part of, and I updated it periodically as there was new stuff to record.
That list has been unbelievably useful now that he is a senior working on his college applications. When you use the Common App, you can only list 10 activities, and you're supposed to list them in order of how important they are to you, and how much time you spent doing them. It's hard to do that if you don't have something to work with. Having a detailed list helped my son group some small activities together, reasonably estimate the actual amount of time he spent doing things (if you forget all the little things you did, you tend to underestimate), and remember things all the little things involved in a club so that he could develop a detailed resume and present the best summary of his Activities on the Common App.
So, absolutely, if you can get in the habit of writing your activities down, it will really help you in a few years.
That said, when you think about joining activities during high school, do what you genuinely feel drawn to. Don't do something just because it sounds like it would look good on your college application. Part of being in high school is trying things that sound interesting, discovering what you like to do and don't like to do, and figuring out what you are good at doing. If you do that, then by senior year, you will likely have a list of activities that really reflects who you are as a person. And you will have good essay material. That is what colleges will ultimately be interested in, i.e., who you are as a person and how your genuine abilities and talents (not something contrived to look good on an app) will contribute to their campuses.
Good luck, and enjoy high school! It will be your senior year before you even know it.
The way I take that question, it is just designed for the school to know whether you are interested in going on to some kind of grad school and if so what kind. As far as I know, your answer does not commit you to doing any kind of pre law track or activity or anything like that.