Even with all that, I thought elves to be an immortal race, so they are just long lived? Jaheira looks old af, mostly body than face. More of a surprise than complaint in that regard.
Elves are long lived, but Jaheira is only a Half-Elf so does age gradually. Don't know about Imoen; in her original epilogue she starts hanging out with Elminster. Can't remember what happened to her in the novels. Probably dies. Almsot everyone else unlucky enough to be in them in does (including Jaheira). There's another thing where she's a half-vampire or some nonsense. In any case, as she was a powerful mage at the end of BG2 its not out of the question for her to still be around if quite a bit older.