Your girlfriend is pregnant with your child. Listening to her concerns is important, as the decisions she make affect you very similarly.
Because the situation involves both of you, it's important that share your own thoughts and concerns with her. This is a new situation for you, and your best bet is to share with people who care for you.
It's possible that you and your girlfriend are not in agreement with the decision she will make with her pregnancy. After listening to her, it's important to be honest with her, so she doesn't feel overwhelmed.
Some men feel that their girlfriend's pregnancy doesn't affect them, and that they can simply leave the situation. Not only does leaving her make it harder for her, it also can be hard on you in the future, because if she has the baby, you are still the father. You can't change the situation you're in, so make the most of it.