Did I just wreck my chances at a T50 school?

Hello!

I am currently taking AP Physics 1 this year and had always planned on taking the AP test, but after doing pretty badly on the first test of second semester, I decided against it. However, as the semester starts to end, I will end up with a predicted grade of an A for both semesters. My family makes enough for me to pay for all my AP tests. I will be taking 4 other AP tests this year.

Did I just ruin my chances at a top school because I’m not taking an AP test for a class I’m getting a good grade in?

You are fine. Plenty of students at my D’s school didn’t take the AP tests because of costs. You wont raise any red flags.

No.

As long as you are not required to take the test by your HS you are fine.

No

AP tests are generally for getting credit at a college, not admissions. So it is good to take them if you can.

For example, Stanford says:
Students currently enrolled in AP courses are not required to submit AP scores as part of our admission process. AP scores that are reported are acknowledged but rarely play a significant role in the evaluation of an application. Grades earned over the course of a term, or a year, and evaluations from instructors who can comment on classroom engagement provide us with the most detailed insight into a student’s readiness for the academic rigors of Stanford.
http://admission.stanford.edu/basics/selection/prepare.html

No, you’re fine. If it really continues to bother you, however, or if you have a secret desire to major in physics… you could take the AP Subject Test in Physics. Personally I wouldn’t worry about it.