I mean, it's really not all that different from how our first couple started.
Yeah, the lines and sentiments are very close as well (Yori & Shiho's). There's been loose main couple parallels it's been pushing (i.e Yori to Shiho, Hima to Aki).
Yes, it's supposed to parallel HimaYori's relationship, with a key distinction. HimaYori's relationship doesn't have the messy history of one them already running out on the other one when her love did not pan out. Hima did not have the pressure knowing that could Yori potentially ghost her and act like an asshole again when she doesn't get her way. So while there are structural similarities, it's not the same dynamic in context.
She's not afraid of losing a friend. She's drawing a direct comparison between a potential romantic interest and her current closeness to Shiho, which she's still struggling to confidently label. She's not worried that Shiho would abandon her. She's worried that their current level of closeness and intimacy would not be the same.
I feel like this conclusion requires more reading between the lines than I'm comfortable with. The explanations in your comment feel like assumptions based on context that wasn't provided in text. The author could have completely left out page 25 and it would have been a fine confession that conveyed the same feelings. By including page 25, the author is bringing attention to a critical issue that Aki's worried about, which is that Shiho would abandon their friendship if things remain as they are. In your interpretation, you feel like that's not actually what Aki means. If that's the case, then this is poor writing on the author's part, because that leaves so much open to interpretation in a scene the readers meant to feel good about. This is a reoccurring problem with this series and that's why Shiho is such a polarizing character, because readers can easily interpret the scenes in drastically different ways. (Another scene that comes to mind was when Aki said "The one at fault is me" after finding out about Shiho's feelings.)
"I don't have romantic feelings towards you, but I don't want to be apart from you."
We can see it as something wholesome because of the gorgeous art and because we know that Aki is a great person with no bad intentions, but it's a dangerous game to play, especially when on the other side is such a mentally fragile person.
You left out the most important parts of that segment. She said "If I were to think about whether I have romantic feelings towards you right now..." and "I'd probably thinks it's not that kind of feeling just yet."
With the heavy emphasis she's putting on the "not yet", it's pretty clear that she isn't "just" asking her out bc she's desperate to keep her around as a friend. She absolutely goes into this confession with the expressed intention to come to love her romantically as well.
Even if it's not "just" because Aki is desperate to keep Shiho as a friend and Aki is expressing the desire to eventually love Shiho romantically, page 25 still leaves room for the interpretation that keeping Shiho in her life is one of Aki's main motivations for asking Shiho out. Shiho's reaction to the line, "If we were just to remain friends, and I found myself another lover, would you still stay with me as we are right now?," indicates that she hasn't completely grown out of the same mindset that caused her ghost in the first place. That's why I feel this confession happened too quickly. Yes, Aki didn't have the time to figure out her feelings yet, but she pulled the trigger before she was ready to prevent Shiho from running off again. I'd just feel better about this confession if the author had shown a time period where Shiho was friends Aki without expecting anything romantically out of her before Aki asked Shiho out. The time period doesn't even have to be that long. I'll even take a month (I know time is subjective), but it's only been like a few days (a week?) since everything happened.
To be clear, I like Shiho as a character and was rooting for AkiShiho to happen. I just wasn't happy with the way it happened. Not that I wanted the author to drag out this arc any further, but it would've been nice to see a few more chapters of the cast living their life (maybe start a new arc) while AkiShiho's repaired friendship simmered in the background before they got together.