Nine

So I met BioMom nine years ago tonight.

We were at a party of a mutual friend and toward the end of the night it became clear that the very next day was BioMom's birthday.

I asked her how old she was.

She answered the literal truth, rather than how old she would be in a mere two hours.

I should have known what I was getting into.

Happy Nine Sweetie!

I'll leave the other relevant number here in its ambiguity, just like you did.