Pregnancy.

So I know where all here to help eachother , its like we are family. If you have any rude comments please keep them to yourself , its hard enough as is . So , i am 15 years old . And im pregnant. I do not know how to tell my mom & i am scared of the way she will react. More because my sister that is 18 didnt even get pregnant at such a young age . & my mom always told me not to do what she did , because she got pregnant at 16. So , any advice ? What do i do. Im scared ..