From the context, I think there is something I'm missing. "長い" might have a slightly different meaning when addressing food... because I can't think of why "long" would put Kamikaze on edge like that.

cyrilkhan said:

From the context, I think there is something I'm missing. "長い" might have a slightly different meaning when addressing food... because I can't think of why "long" would put Kamikaze on edge like that.

She's referring to her experience of making onigiri.
"My long-time experience in making onigiri isn't just for show, after all!" <---what she wanted to say, but she realized this would mean she's revealing her old age(Taisho-era ship, much like Kongou, Tenryuu, and Nagato)....so she stopped. This is also one of her in-game lines.