How much do senior grades count?

I’m applying early action to Yale, and I was wondering how much my first term grades will matter. I am taking 4 APs this year (the most my school allows). I have an A in AP chem and physics, but I have a B+ in bc calc and an A- (almost B+…) in AP lit. Both of these APs are the hardest ones offered at my school, and I have the hardest AP lit teacher (he still hasn’t given out any essay grades above an 86).
I’m not by any means slacking, I’m actually trying my very best. I’m concerned though because I did get all As the last two years, does this show a downward trend?
This year is actually hard also because my school has moved to a new schedule, will colleges know/care about that?

Thank you for looking at this…lol I know this may seem small but I’m really freaking out