Is it weird to send this email?

I'm leaving my job really soon.

There is a chick who is really nice. I think we met in a work training or something about 1 year ago.

She works in a different department and had worked n a different building until recently. She works in a different area now, but within the same building.

Everyone is in a shared office so I don't want to go to her and be like,
➡️➡️➡️ "hey, I'm leaving so let's exchange numbers and keep in contact"

I don't want everyone else knowing and "asking me questions.

Is it weird to put that in an email?

I literally just say her yesterday. I spoke to her but I didn't tell her cause there was too many people around (social anxiety 😔)