pregnant and endo

Sneki
I found out that I am 4 weeks and 5 pays pregnant. How soon will I know that it is NOT an ectopic pregnancy? I have my doctors appointment scheduled before I announce it to the family and friends but I want to make sure that the baby is in the uterus first. Would I know by now if it's an ectopic? When would I know that it isn't ? 
Help please