Why Don't I Get A Say?

I am a 21 year old software engineering student. My fiancee is also 21. She is the best thing that ever happened to me, and the light of my life. We met in high school, and have been together since we were 17. We plan to get married once we graduate next year. I love her with everything in me. We have been sleeping together since we left for college, she is on birth control and we use protection. About a month ago, when she was changing birth controls, we got drunk, and forgot to use a condom. Apparently, when you are changing birth controls, it doesn't work, because she is pregnant. I want her to get an abortion, and she knows my views on the matter. We can't afford a baby now, and need to finish our educations. But she is against it, and has told me that either I want to help raise this baby, or to get out, because there's no way in hell she's getting an abortion. I know the whole "my body, my choice" line, but why don't I get a say in her potentially changing my life forever? I want to have kids with her, eventually, but I just cant see it happening now. I know there's a big debate about guys not getting a say if the situation's flipped, but why not in my case? I know I can't make her get an abortion, but I just don't see why she doesn't see my point of view

tl,dr- Fiancee, with whom I have been in a relationship for over 3 years is pregnant, I don't want to keep it but she does