At what week should you tell your boss?

VLa • 👦🏼👧🏼👼🏼

I was hoping on waiting as long as possible to tell my boss ( 15 weeks being the max although I’d rather wait longer lol) what is a general rule or when should you inform your boss of your pregnancy? I’m not showing too much yet I’m 8 weeks tomorrow. The trouble is having to constantly leave for doctor appointments and I feel like at some point my boss will catch on anyways