ILTV is fair: Rei was at least 25+ when she 'died', Claire's 15. Though LN 5 'explains' the isekai and makes things trippy.
Fed Up Office Lady counts too, though hard to really apply 'grooming'. But the MC is a summoned OL, and Lapis is... actually I'm not sure we have an exact age, or if this school is like high school or college, author playing it coy. But it looks more like high school, with the uniforms and such.
I dunno about Bully, though. I couldn't find any clear evidence of Yvonne's first-life age. She's experienced subway crushes, but so could a Japanese high schooler. She's never dated anyone before. She doesn't really think much about her past life outside the gameplay, but I think there's a memory of a friend jumping off a high school roof.
So there's no clear evidence she's really older than Elsa, apart from living childhood twice, and yeah the "oh we can't, I'm too old" was bizarrely out of nowhere, especially after already getting together and making out.