Please help!

I am NOT TTC as I am only 16 years old. I have been sexually active for 2 cycles and am on the pill (as well as usually using condoms and if not a condom always withdrawal) because I am on the pill, my periods are extremely regular and I was supposed to start yesterday. However, I still haven't started. I'm totally freaking out and can't think about anything else. Is it too early to take a test? Also, my pills yesterday and the day before were placebo pills, but I'm supposed to take the hormone pills again today. If I don't take a test and I take the pills but it turns out I AM pregnant, will this hurt the baby? Thanks for any advice/wisdom etc.