Heart beat question

I am 6wks 4 days and my friend is determined to tell me you can hear it at 6 weeks... I told her every pregnancy is different but she didn't listen she keeps saying I need to go to the obgyn but I want to wait at least until week 8. I was planing on going about 12-13 weeks but everyone keeps putting me down.... I wanted to wait because I had an early miscarriage last time at 5 weeks and like 2 days so      Really what I am asking is when should I go to the obgyn? When can I hear the heart beat?