Importance of extracurriculars

I'd say they're pretty important but not 100%. You should keep your GPA up as your primary concern, and if possible, take the SAT or ACT because a good score can help make up for gaps in your resume. Also, don't discount things that aren't official--if you babysit a sibling frequently, add that! If you help take care of your aging grandparents or if you live on a farm and help with the chores, add that! Maybe you've been going to a specific gym for years--have the receptionist check how many hours you went and add that! Everything is important. Also for the ones you have now, it might be worth it to add a note saying how long you've been doing something if it's a significant amount of time (e.g. if you've been volunteering since 6th grade, noting that can show long-term commitment to things that are important to you). Maybe consider adding one more thing if you can, but it's not the end of the world if not as long as your GPA, course load, test scores, and essay are good.

VERY. Extracurriculars and leadership show colleges, particularly top ones and Ivies, that you're not only passionate but willing to act on those passions and make a difference. If you spend a lot of time on those things, that might make up for a lack of variety in your profile. Colleges do like to see depth rather than breadth. If you're still concerned, you can always start a passion project of some sort, one that you're actually interested in and take very far, before application season. However, at this point I'd just suggest going deeper in those you're already involved in.