First ultrasound !

So I have an appt for a vaginal US this Friday 7/8/16. According to glow I will be 7 weeks exactly. I'm just wondering if that's a little early to hear a heartbeat??? I had bleeding a few weeks ago but my HCG went up afterwards so I'm still pretty nervous and anxious. I can't remember how many weeks i was when I went with my son. Have you ladies heard heartbeats at 7 wks ??