Inspired by several recent questions about siblings.
My little sister was born a day¹ after me. Yet, we are not twins. I love her very much.
Now the question:
Where am I?
EDIT: yes, the intended answer is about (realistic) people in our real world.
She's a woman, I'm a man... but there is no incest.
Tags are important.
the specific language that fits the question
and I'll reveal the answer in some days if not guessed by then.
¹ Not really important that this is one day - could be a few days, a few weeks or whatever...