AH...the pregnancy scares of our youth years.
Been there, done that...they're usually false alarms.
If she is pregnant, you better pray it's the other guy's. She sounds like a "busy body" to me...you're better off without her. BUT, if it is yours, step up, be a man and take care of things.
I believe she can get a paternity test before the baby is born...if I'm not mistaken. That would be a good idea.
Be careful! You're too young for this.