I am currently a freshman in high school. As freshmen we take physical science, in 10 grade we take biology. I have been thinking recently about taking a summer biology class and asking to see if they will let me take Ap bio next year. I spoke to some upperclassmen about taking Ap biology and they told me that this is a hard class, and the fact that the teacher doesn't teach makes it even worse. Next year I would be taking Ap world and Ap calc ab (if I pass the test this summer). Would it be too challenging if I take ap bio with these two ap classes?
I don't know your exact situation, but I assume you want to take this biology class over the summer because you can't take AP Biology at your school unless you pass an introductory biology class first. Before you commit to the class, think very carefully about how important it is for you to take AP Biology next year. If the teacher for AP Biology at your school is really as terrible as these upperclassmen say, you might want to think about a slightly different plan. If there's an honors Biology class that has a better teacher, you could take that instead, and just self-study for the AP test on the side. You'll still get AP credit, but you'll avoid a bad classroom experience. You'll also have the summer to get a job, work on other extracurricular projects, or just relax.
To answer the second part of your question, taking AP Bio, AP World History, and AP Calculus AB at the same time would be challenging, but it's doable. Only you know your limits (and the extent of any extracurricular commitments that might make it more difficult), but I assume you're an intense student who is probably capable of handling the work if you're even thinking about this in the first place. The main concern is the breadth of the content in both AP Biology and AP World History. Both cover a ton of information, so it will be stressful if you have two tests to study for at the same time. Think about your strengths as a student and whether you'll be able to handle the extensive reading, writing, and analysis that these classes require. I would also be careful about which other classes you choose to take in addition to these three. A tough English class with a heavy work load could change your situation from stressful to unmanageable.