Goddess of perpetuity

Perpetuity is a funny word but I couldn't find a better one to describe aspects of my lovely sister. And i did have to get on the thesaurus! She is a constant, doesn't appear to have any flip outs, moods or irrational behaviour (like me), she's well balanced and consistent with her kids and everyone else, and our relationship as sisters has and will always be there. So it works, but it is a weird word! And this pic will need changing to one taken in daylight as it does the colours no favours at all.