I told my teacher I wanted to major in biology, and that has changed. Unfortunately, I just remembered that I had to tell my teacher this. Am I screwed?
No.
People have multiple interests and in theory, you don’t know what your teacher wrote about. You don’t know she mentioned it.
But if so, so what. They’re not looking for what you’re interested in.
They’re interested in learning more about you and what you add to the community.
So relax - this happens regularly and you have zero to be concerned with.
Even if she did mention that you want to be a biology major, it’s unlikely to make or break a decision.
In many instances, though, biology is one of the most competitive majors because many high-stats pre-med students apply to it. If a school directly-admits to a major and you have ECs that scream pre-med, it’s possible that an AO will wonder if you are trying to game the system by applying to a less competitive major.
It is very unlikely to change a decision, though. These kinds of errors probably happen often. Don’t fret — it’s going to work out.