Life isn’t exactly an “accident.” Your parents had to make a deliberate choice to have sex. Now, there is some sort of probability involved in the chances of pregnancy, which sperm cell creates a new person, and that new person actually surviving all the way to birth and beyond. But ultimately I wouldn’t call life an “accident” outside of some very specific scenarios involving the parents. Your parents chose to create a new person, and that new person was you.
The purpose of life? Who’s to say? Ask ten people and you’ll get ten different answers. Some people spend their entire lives trying to answer that for themselves, others ignore it entirely. It’s a question only you can determine the answer for yourself. But my answer to the question will likely be entirely different from your answer.