Jesamyn is right sarah...And I know youre scared to tell them, but think about it, if you are, they are going to know when your belly gets bigger..They are going to find out soon enough anyway...Show them that you are responsible and strong enough to come to them about it....Even if they freak, assure them that you need and want their support anf help.
I got pregnant at 17 and telling my mom was terrifying, shes kinda mean, and after I did, she freaked and things were rough, but she did come around, and helped me alot. Now hes alomost 9 and still her pride and joy...She apologized for ever expecting me to abort him or give him up and really is proud of the way I take care of him...
You need to swallow your fears and think about what is best for your (possible) baby. If telling your parents and dealing with their wrath will help you get prenatal care sooner, do it. Be strong. You think telling them is gonna be hard, wait till you have to go thru motherhodd....Thats the scariest thing you will ever do
trust me....