When to reveal pregnancy to parents and in-laws?

This is my first pregnancy, just found out a few days ago. My parents will be first time grandparents and I cannot wait to reveal the pregnancy to them, but at the same time am a bit "pantang". Was thinking maybe the 8 week mark if everything goes smoothly, but am afraid I won't be able to wait so long!!!...When did you reveal your pregnancy to your parents/in-laws?