There are two very important people to consider here - you and your baby. You need to make your own decision on the situation (whether to keep the baby or not). Once your decision is made (or if you can't make a decision), that is the time to speak to your parents.
How about talking to the parent who you are closest to first? Then ask that parent to talk to the other one. They won't be happy at first, but let them get over the shock (which may involve quite a lot of shouting and unpleasantness). If they love you, they will stand by you, whatever decision you make, and support you all the way.
If they can't find it in their hearts to support you, there are lots of organisations out there who will be able to help you. Depending on your home circumstances, you might want to find those organisations near where you live before speaking to your parents. You could either look on a search engine, or speak to your family doctor.