It won’t be easy telling your parents, but it’s best for your child that you tell soon. Specially if you haven’t seen a doctor, and aren’t taking prenatal vitamins.
My parents happen to figure out that I was pregnant, about 2 months after I found out. I tried figuring things out on my own, which wasn’t a smart choice. My mom questioned me, expecting me to tell her I wasn’t, and just brush it off. She was in shock when I told her I was. You parents might be upset and disappointed at first, but hopefully they grow to support you in any decision that you make. Just remember, that this is your child, and you make the choice.. not them.