Yes, I'm Transmigrated! What?! I'm Mother of Five Children? YITWIMOFC

Sally transmigrated to the world of heroes and demons. To a body of 320 y.o female elf.
Being old is fine, elf is an eternal beauty. Being a main wife of hero's harem... well, hero is missing so it's fine.
"Wtf, god, are you kidding me?"
Now, the 20 y.o Sally is a mother of four. Oh, no! There is a soon to be born baby, so it's five.
Roona, eldest, 15 y.o human girl.
Argee and Arfeena, twins, 12 y.o half mermaid boy and girl.
Rooga, fourth, 6 y.o half elf boy.
Soon to be born baby of a demon princess... let's think about name later.