Most Helpful Girl
You and she sit down and talk about what you each feel is right. At this point the choice is ultimately hers. You made your choice to risk a pregnancy by having sex. If you both need to, get your parents involved. Start preparing yourself for the possibility of paying child support. Even if you didn't want to have a child this young, you will still have to be the best dad you can to that child if it's born, don't wuss out.
You are clearly not genetically sterile - you were never tested, and now you got someone pregnant. There's your clue.
Most Helpful Guy
There isn't an accident about it. You put your penis in her vagina and came in her. You made a huge mistake not getting tested and not having any kind of protection. If she wants to have the kid then you have to deal with it. If she doesn't want it either then you lucked out.
So you should get tested if it comes out you are like your uncles then she cheated on you if not then you are like your dad and can have children.