Hello,
Congrats on getting into UC Davis! I always wanted to go to that school, but unfortunately didn't get in. I quite understand your feelings about not being able to care for a child at this point in your life, it was one of the reasons I got an abortion. I found out I was pregnant just before I found out I was accepted at my UC school, and had just turned 20, I have aspirations to become a physician.
Like Birch said, you have to do what is right for you, and really, only you will know. Like Birch, there are many women (even on this forum) who feel no regret and there is no shame in that, and like the woman you spoke with on the hotline, it wasn't the right choice for them, even if they felt it was their right choice at the time.
Please don't let anyone sway you either way, it has to be your decision alone, and I wish you the best of luck either way.
Btw, I am still with the person who fathered my first, been together 3 years. I'm young as well (21), we're both continuing with our educations (he's graduating this semester!) and he just landed a great job. Things will change for you either way, but it does not have to be bad.
You sound like a smart girl, just follow your instincts, you are very young, and if you feel that you are not ready for a child, no one should make you have one.
Feel free to contact me through private messaging if you feel the need to talk!
-Amino
*edited to fix my wording*