I've recently joined a new workplace and it'll be my birthday soon. I don't know colleagues well enough to have mentioned it and (as far as I'm aware) nobody else's has taken place while I've been there. Should I provide cake or something at lunchtime? We work in isolation for most of the day, so would need to send an email, which almost seems like too grand an announcement really, but I'd feel weird keeping it a secret, as I feel like it would come up in future! Probably over thinking this, but would like some advice.