Just be supportive, bring her to a positive and calm state of mind. When she comes to that place maybe she will change her mind, maybe she won't, but you can only be supportive in an effort to 'extend' the time of thinking about the right decision rather than make brash decisions based on fear, or the fear mongering of others like some here. You have to weigh the positives with the positives.
Having a child is life-changing, but of course it can be and usually is a wonderful thing which someone couldn't imagine it would have been. So the positive is a high probability.
Thinking that it will be the end of her free independent life, is true to a point, but as to what that life will be or whether it will be better having gone through with an abortion, is unknown. So the positive here is just down to chance.
If she has only just found out she is pregnant, then it is probably panic and shock, especially in the case of 'what will my parents think?' Usually we think they would think the worst, but in many cases where we think that, parents are actually supportive.
If she has a close and trusting relationship with her mum, then it would be good for her to tell her mum privately and ask advice, she will be surprised at the reaction. If she doesn't have this relationship, then that can be a challenging place to be, and the most positive support should come from her friends.
No-one wants to be confused with fear, and make the wrong decision out of fear. It is THAT which is often regretted and haunts a person in the future.