I got two B's second semester junior year of high school. How much does that ruin my chances of getting into a good school?

I don’t think it’ll make a huge difference. If you took the AP exam for either class and did well on it (which you don’t know yet), it could help to report those scores.

Overall, your record is strong. Definitely make sure you keep your grades up senior year. Remember that as you move through high school, the classes become closer to the ones you’ll take in college, so they signal more to a college about your ability to do the work at college than freshman classes do.

For your part, since you are obviously a strong student, think about why you didn’t do as well in those classes. Use this as an opportunity to learn about how you learn. Did you rely too much on memorization? Do you need a better way to figure out if you really understand concepts? Are you focusing on the right things when you study and prep for tests? It can be hard to focus on mastery when grades seem so important but you have a chance to fine tune your study and learning skills!