I, uh... don't see any textual evidence for that position.
I mean, it's perfectly logical, but it would also be within the logic of this story to say that by pulling the future towards her she was going to disappear from our stupid racist/sexist era and reappear in a future where we don't treat people like that anymore.
So, based on this interpretation she suddenly has powers that she never exhibited before (Unblinking's climax) and can now control what she has been unable to control for (30? 40? 50?) years.
That doesn't jive with how I see here character developing.
Throughout the story she is slowly losing her sense of "self". She doesn't know who she is, because she so many people. She could try to be the sum of those people, but her "canonical" self is broken, it has no sense of continuity due to the frequent jumps. The past lives are more real to her because they had a beginning, middle and end. With no temporal discontinuities in between. Whereas her present self, her canonical self, cannot finish a sentence without getting lost in time.
So, she tries to not be the sum of her past lives but instead just "this" life, the canonical one. She does that by killing the past lives as soon as possible, before she can forget what she was doing in the canonical life.
So at this point in her life she has put aside her sum-of-lives approach and is trying to live just this one life.
All of it – the self-imposed silence, the suicides, the banishing of her fantastic past to the basement of her brain – these are the price of a normal life, of friendships and a marriage and a steady job. Mundane though it is, Makeisha reminds herself that this life is different from the other ones. Irreplaceable. Real.
That fails as well. Why? Because even though she is trying to live just the one life, the past lives are still a huge part of her. And you can't repress such a large portion of your life without consequences. You are the sum of all your experiences, if you decide that a lot of those don't matter, aren't important, are less important than who you think you are now, then you lose a large chunk of who you are.
Still, she misses the past, where she has lived most of her life.
And then, suddenly her past lives, which she has tried so hard to repress, surface in such a way as to negate her existence.
When she gave up time travel, she never thought she had surrendered her legacy, too.
So she tries to prove to herself (and to the world) that her past lives existed, they mattered.
She leaves messages that constantly get misinterpreted, attributed to others, lost or forgotten. She invests so much time and effort into proving that her past lives happened, that they mattered, that they are a part of herself that she loses touch with her present life, the one that used to be irreplaceable, real.
She is fading from the present. She forgets to eat between jumps, loses weight.
Her present self, the one she used to think was the real one, is fading, just like her past lives.
Makeisha wonders how many decades or centuries until this signature is also altered or lost or purposely erased, but she touches pen to paper anyway.
She no longer knows who she is or when she is.
Perhaps it is not the past that is yanking her away. Perhaps the present is crowding her out. And perhaps she has finally come to agree with the sentiment.
So what are her options? She could try to kill herself
But no. No. The self-murders were never for herself. Not once.
That is a very difficult line.
First of all, the "never for herself" part. She thought that she was doing it to have a normal life. If she wasn't doing it for herself, then who was she doing it for? The other people in her life? That seems like a lot of effort to appear to being normal, and it never even worked. And why would she care what other people thought about her if not for her own well being? Therefore I propose that she
was doing this for herself, but the self that she was doing this for no longer exists (or never existed).
Second, why is this here? It seems very strange. "Oh no, I don't think I belong here anymore, what should I do with myself? I'll kill myself. No. I've never killed myself for myself before". How is not doing it for herself a reason not to kill herself? Therefore I propose that she needs to do something for herself. For her self. Only... she has no idea who that self is anymore. Perhaps she never did.
So, here she is, the shattered remains of her self identity lying in pieces around her, marked off by crossed out sections in history books. She needs to do something for herself, for her own good. She needs to somehow assert her identity to herself. The past never seemed to work, and neither did the present.
So what does she do? She pushes herself into the future. Why does she do that? Why does she use some previously untried power? Because she has nothing left to lose. She has lost herself in the past and present, and has nothing to look forward to in the (mundanely reached) future. She needs to perform some act that is hers, and hers alone. So she tries to jump to the future.
Does she succeed? We don't know. I think she did not. There was nothing in the story to support the fact that she could willingly jump anywhen, let alone to the future. Of course, she has not returned. Which means that she clearly left the present.
Did she not return because she doesn't want to? Or because she can't? We don't know. But I think that she can't return, because she is lost to time. She hardly seemed to be in the proper frame of mind to control some sort of ephemeral power that she has never been able to control before. And to control it so well that she can willingly find a place in time where racism and sexism no longer exist. She had a lot of push and drive to be gone, but not a lot of "oomph" to actually be able to control it. That's why I think that she was successful enough to push herself out of the present, but not successful enough to actually land anywhen.
And somewhere, inside her, she knew that that would be the result. She spent her entire life trying to find out who she is, and she finally found an answer: she is a person who can bend the fourth dimension. And that is all she is. So now she is lost, in the fourth dimension.