I think that you are worrying about something that really isn’t a problem. Both classes are good classes to take, and classes that you will want to take at some point in high school. You have plenty of time to take biology.
You really will be a stronger student in a year or two than you are now. The teachers do have plenty of experience with seeing strong students “overreach” and take classes that they are not ready for.
Do as well as you can in the classes that you are taking. This will help you do well next year.