I just finished my freshman year of high school with largely Bs and Cs on my transcript while taking honors classes. If my grades for the my next 3 years of high school meet the standard of these schools, and the rest of my application (SAT scores, EC’s, etc.) do as well, would I still be able to be accepted into a selective university?
This depends upon the university. There are a few pretty strong universities that don’t look at your freshman year at all (I think this includes most of the Universities of California, and every university in Canada; I am not sure if there are others). For any university, your sophomore and junior year are going to matter a lot more than your freshman year.
As such I would suggest that you try to pull up your grades significantly for the next two years and then see where you stand.
Perhaps more important at this time: Do you know why your freshman year grades were disappointing? Do you feel that this was caused by something that you know how to fix?
My poor grades this year were caused mainly by a lack of effort, therefore, this problem can be fixed more easily than other possible reasons for poor grades, such as mental illness
Elite universities, as in top 10’s (ivies, stanford, caltech, others) use academics as a filter. Basically, if you don’t meet a certain standard of academics, they won’t look at your app. If you do, then the application basically comes down to your EC’s and essays. This means that you could still get in if you make near perfect grades (3.85 UW at least IMHO), but isn’t enough to get you in.
IK a lot of people are like “can i still get in with bad grades”; the better way to ask is to post your whole stats list with your grades too.
Elite colleges, however, are going to question why you made such bad grades. If it’s from a lack of effort, that’s actually worse than from, say, a mental illness or bullying, since it shows you don’t have much drive in school. In your interview, I guarantee you in the interviewer would ask you why you have bad grades. Lack of effort will almost certainly cause your app to be dropped.
Thanks for the response! Would a top 10 university still drop my application if I had an upward trend, as in, I start to put much more effort into school during my sophomore, junior, and senior years, or would my lack of effort during my freshman year alone still be enough for these schools not to consider me?
If you showed an upward trend with your grades you could still get in.
If you get anymore C’s or 2+ more B’s I think there will be a good chance of being disqualified.
Thanks for the response!
Sure you can still get in. But you need to fill a need that is really desirable (URM, athlete, mega-donor).
Top 10 universities are reaches for everyone, even students with no “blemishes” on their academic record. There is basically no point in worrying about Top 10 schools until/unless you have a flawless sophomore year under your belt and are well on your way to a flawless junior year, with a great PSAT score to boot; and even then, you will need to identify matches and safeties that you’ll be happy with. Worrying about super-elite colleges is not a good starting point for you right now. Will you be able to get into an excellent, selective college if you do well from now on? Yes, definitely.
What are you interested in studying? My suggestion, if you find it motivating to think about college, is to identify a few selective-but-attainable schools and get to know them well enough to feel excited and motivated by the prospect of going there. Not a top 10, just a few excellent, selective universities.
Getting into a mindset, at your age, that you won’t be happy unless you get into a top 10 university is kind of like saying you’re not willing to ever have a partner unless they’re a wealthy celebrity. It’s a bit… limiting. 
The important thing is to have a successful year next year and get things on the right track. Good luck!
“Would a top 10 university…”
Top 10 universities are a reach for students who have all A’s and nothing else over their entire lives. I have some experience with daughters who had pretty close to that (either one or two B+'s in their life prior to university). With even one year of B’s and C’s top 10 would be tough.
If you can pull off nearly all A’s from now on, then top 50 would be possible. Top 50 outside of California or Canada might be possible.
You can do very well with a bachelor’s degree from a top 100 university. When I was in graduate school (at a “top 3” university) there were lots of students there who had done undergrad at their in-state flagship university, most of which were not top 30.
If you have ambitions to go to a highly ranked university, you really need to pull up your effort very considerably from now on, and see where you stand in two years.