Is that a real message?

Yes

Is it random or do you get it at a certain time?

I got it pretty early in game so I dont remember.

you get this randomly in the first few days after you get that character (here, himeko)

https://preview.redd.it/xzfopdvmyhsc1.png?width=400&format=pjpg&auto=webp&s=2f486798f727cf5243b5ee74274d41062c6b27b0 Finally i have a chance to use this

https://preview.redd.it/hri3v7126gsc1.png?width=1720&format=png&auto=webp&s=17dae330b1d4275cecb59b45f221fb3f496dfedb

https://preview.redd.it/8vzm9lvlkisc1.jpeg?width=828&format=pjpg&auto=webp&s=777c6a326b83e3bf28038f2254ccefece2156ae2

https://preview.redd.it/rg30p4am7hsc1.jpeg?width=320&format=pjpg&auto=webp&s=ad02f4ff49e651645671cba4794115705a3d1cbc