I want someone to tell me to stop her

@MaxZie

To make things easier for me to explain, let us call the fetus/embryo a ‘person’. From what you're implying (correct me if I'm wrong), that ‘person’ is a victim. Now, I ask you, is a pregnant woman not a person who is capable of being a victim as well?
Have you asked why the woman would want an abortion before saying that she is a killer? That 'person' may have a future but so does the woman. If the woman were to die physically and/or mentally, that is a great loss too.

Creating life and giving birth is not something as simple as "giving it a chance". Agreeing to have a baby is no simple matter. When someone says they want an abortion, they would usually have thought of every possible conclusions to keep or abort the baby, all the bad and the good. If, after making one of the hardest decisions, results with the conclusion that they do not want to keep the baby, then it means they mean it. Whether you believe it is immoral or not, it is not going to stop them. They would do anything, even performing an abortion on themselves and possibly killing themselves in the process, to get rid of the 'person'. If the woman were to perform an unsafe abortion on themselves and die because of it, who would be the killer? The 'person'? Themselves? Or the people stopping them from having a safe abortion?

There are two examples that I want to give, I'm not talking about your friend's gf, I'm just giving examples to explain.
Example 1, the deceased needs consent from trusted family members for an autopsy. Someone who is pronounced brain-dead and did not sign the waiver for organ donation requires consent from their family members. If the family do not agree, then the professionals have to agree with their decisions. It is not morally right for the forensics to cut the body open and take the person’s organs or get evidence for a crime scene just because they want to. Similarly, a pregnant woman themselves did not consent to having a child. The deceased and someone who can no longer wake up has more voice than someone who is alive. One might argue against this by saying, “what if the partner wants to keep the child, or trusted family members? In the example you gave, they got consent from family members.” That is correct, there is consent from family members because the person is dead, they can not make decisions, but that’s not the case when someone is alive and can make decisions. The woman giving birth is not a vessel, but a human being. We must remeber that. If the woman agrees with the continuation of the pregnancy, then they are not obligated to take care of the baby, and the person who wants to keep the baby should take full responsibility. Again, that is still a choice made by the person giving birth.

Example 2, imagine that someone has a baby in one hand and an embryo/fetus in the other hand. It’s at gunpoint by the person holding them (pretend there’s a third hand lol). You get to choose which one lives. If you choose the baby over the embryo/fetus, then that means you see a difference in their futures and experiences in life. It would be basically impossible for you to choose which one lives if you believe that a baby and an embryo/fetus are the same. If you can’t choose between the two, let me add another variable, you can also choose the person holding the baby and embryo/fetus to die. Let's pretend you choose them because your excuse would be that the person was going to kill a life, but are they not considered a life too? If you were to choose that, then you would be the one killing, and like what you're implying, killing another human being is wrong. Additionally, it would also mean that you would be saying it’s morally right for you, a random stranger, to decide who lives or dies. Us, who are random strangers and is not affected by it in any way, gets to argue whether abortion is morally permissible or impermissible. That doesn't sound right.

Futhermore, there is a difference between what's "right" and what one "ought" to do. Imagine that one day you woke up and your heart is being hooked up to the heart of a famous actor, who needs access to it for nine months to survive. The actor is innocent because they did not ask to be hooked up and have no control over it. You can choose whether to unplug or not. You have no obligation to remain hooked up to the actor. If you are permissible to unplug yourself from the actor, then it is permissible for the pregnant woman to unplug themselves from the embryo/fetus. Now, let's change two variables. You, who is being hooked up to the actor will not have your health affected, and that it would only last a day for when the actor needs access to your heart. The answer would then be one “ought” to allow the violinist to access your heart, but it is not “right” for them to do it. It is not their obligation or is it morally required. However, some may argue that you are selfish, indecent, and/or a killer. All in all, it comes down to this, it is not morally required for woman who is pregnant, or anyone at all to be honest, to sacrifice their health and future in order to keep another person alive. One may or may not “ought” to do that, but it is not morally “right” for them to do so.

I'm not telling you what you should or should not do, nor what's right or what's wrong. You can do whatever you want with all this, I just you to know that this is a lose-lose situation. There will be pain for everyone involved, for both sides. I hope that you would be able to treat them both with respect, care, and love. Like what Shannon Berry once said, "Grief is just love in a heavy coat."