I’m an incoming First-Year at Brown (Class of 2024,) but my advice should still apply to you in a few years once you apply to college.
The answer to your question is: IT DEPENDS! Like many other colleges, Brown’s looking to see if you’re able to consistently challenge yourself in high school (through courses, extracurricular activities etc.) and succeed. I had similar grades to you as a freshman, and if you’re able to maintain your grades/course difficulties throughout high school, Brown will look upon that favorably.
However, I’ve learnt throughout this college admissions process that Brown (and other similar schools) utilize grades/test scores/courses as a way to assess your capability to handle the curriculum at their school, and once Admissions is certain of this, they look to the other parts of your application (essays, interview, letters of recommendation etc.) to get a feel for how you would fit into the freshmen class as a whole. In Brown’s case in particular, the Admissions Office is looking to see how you would take advantage of Brown’s resources and the Open Curriculum (through your essays as well as by how you’ve taken advantage of your own school’s resources,) but also what you would go on from Brown to do and whether the school would be proud to call you its future alumni.
As a sophomore, you definitely have time before college admissions begins. At this point, I would recommend that you continue to research colleges to find ones that you’re interested in, but most importantly, continue the extracurricular activities that you enjoy the most, put a lot of effort in them, and make sure to continue giving your schoolwork your 110%.
Once you are in the process of applying to college, I highly recommend that you apply to Brown ED if you LOVE Brown and would 110% attend if admitted, can present an amazing application by the early decision deadline of November 1st, and you and your family can afford Brown (make sure to run the financial aid calculators in the few months before you apply to college, as its based on the most recent few years of income/tax data.)
Hope that helps! Good luck with admissions in the future!