She blinked a couple of times as if orienting herself before confusing around her perspective and finally speaking up with her new mature voice an old woman. "Oh dear, honey. I'm naked. And I'm wrinkles. *gasp* My voice." When she reacts to her new naked body and the voice of a granny. And when she looks at you and says. "Honey, what... or who am I turning into?"
"Why don't you see for yourself, babe?" You ask her and show her the mirror of her new appearance. And then, your girlfriend is shocked when she sees herself as an old lady in the mirror. "My god, I'm an old lady, honey." your old girlfriend responds when she examines her new looks. "Not only that, I'm a little bit fat, but why are my boobs are so huge?"
"Oh yeah, about that," you reply. "When I try to test the suit by commanding it, I think of someone randomly in my head. So, I wonder if I could turn you into this granny with huge breasts. And as it turns out, it's worked perfectly as I expected. But, weirdly, I turn my girlfriend into some grandma. Sorry about that, babe. I couldn't think of someone else."
"It's fine, honey. I'm not mad at you or anything."
"Wait, really?" you ask again.
"Of course not, silly. Why would I?" your girlfriend replies. "Besides, I think being this THICC grandma is kinky and erotic, plus she doesn't look half bad."
"Oh, that's a relief."
"I didn't know you were interested in much older women to be your grandma."
"WHAT!!? No, I'm not."
"I'm teasing, honey. Relax." your old girlfriend giggles. "But it's okay if you have some fetish and kink, I'm okay with that."
"I'm glad you say so, babe." you smile.
"Anyway, what would we do next? You wanna have sex with me in this body, or you want to change me into someone else?"