No, one class won't kill you as long as you have extracurricular activities, job experience, and volunteer experience on you resume too. Colleges just want to know you're involved in school. I mean good grades look good too but I took an AP class and got a D- during my sophomore year and that didn't matter. I still had a decent GPA of 3.2 (not failing) and my ACT score was only 21. I think my involvement in programs and activities helped me get into Universities and private colleges. I applied to 5 and got into all 5 with just that. I do want to add that it's not a bad idea sticking with AP classes because it prepares you for the college workload. Seriously, you want to adapt to challenging and fast pace classes now so it won't be as hard when transitioning into college. Also, learn how to BS your assignments well..that's what college is all about.