Okay first of all, you are displaying a fundamental lack of understanding of how the books worked in the first place, because Harry Potter was not born as the Chosen One. He was not chosen by fate, he was chosen by Voldemort. Here’s the actual Prophecy that references him:
The one with the power to vanquish the Dark Lord approaches…born to those who have thrice defied him, born as the seventh month dies…and the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not…and either must die at the hand of the other for neither can live while the other survives…
So Harry was not actually born special. Not only could Neville Longbottom have just as easily been the one meant by the Prophecy, if Voldemort had chosen to go to his house first and somehow failed to kill Neville as he did Harry, but the Prophecy itself was just that: a prophecy. As we learn in the Department of Mysteries, most prophecies come to nothing. Because predicting the future is inexact. Divination itself is inexact, and the future is made up of constantly changing events and decisions. People are not, in the Potter books, automatons of fate and destiny going through the motions of their lives without any say in the matter. They are characters with free will, something that admittedly you seem to be unfamiliar with, and Harry isn’t some kind of Jesus analogy either, a “savior born” or whatever.
I will say again, Harry did not have any special powers when he was born! All of those, he received from Voldemort. He was not some great savior mystically imbued with purpose and powers when he was born; he was someone who might be the person that a half-mad woman predicted a possible thing about. It was not until Voldemort himself got involved that the Prophecy came to fruition; if he had stayed away from the Potters, if he had never met Harry, that Prophecy would have fizzled out like so many others. It’s a classic case of “knowing the future inspires someone to try and prevent it and, in trying to prevent it, they ensure it.” Furthermore that Prophecy only says he has the power, and one of them must die; Harry wasn’t fated to kill Voldemort. He was predicted to be someone who might receive the powers that could grant him a chance to vanquish Voldemort, and then only if Voldemort himself gave him that power! Try and move beyond your cliche understanding of the phrase “Chosen One” and actually give some thought to how these books approach the matter, okay? That will help you.
Secondly Lily Potter was a happily married woman with a great support network of friends who, whether Harry was planned or a surprise, chose to have a baby. Although if she had chosen to have an abortion, given that she was in the middle of a war, and especially given that her blood-status as a Muggle-born and her husband’s as a pure-blood would have put their half-blood child in great danger (even aside from the Prophecy), because he would have been evidence of the “tainting” of the formerly-pure Potter lineage, and as such she would be painting a target on her child’s head for the duration of the war, and thus might well choose to wait until after the fighting was over and her side was (hopefully) victorious before she had a baby…well, I wouldn’t be able to blame her for that decision, so maybe that’s how. Because I think people should be allowed to make their own choices, whether that be to have a baby or to abort it.
Thirdly, Harry Potter is in fact a series of fictional books and is not, actually, about real people. Lots of things happen in those books that could not and should not happen in real life. For example, I love Hogwarts as a fictional magical school, but if it was a real place, I would have several issues with its curriculum, for starters…
So in summation, you don’t understand the books you’re talking about or how the real world and fiction differ, apparently. And that’s how I can be a fan of Harry Potter and someone who supports the rights of people to have abortions: because I do.