If you charted did your baby every measure behind in 1st tri?

TeachGirl323

Hi ladies,   I am lurking from first tri with a question.  I charted and know when I ovulated (assuming FF is correct).  I had my first u/s at what I thought should be 6 weeks 6 days but baby measured 6 weeks 1 day (so five days behind).  The heartbeart was 139 though, and the doctor did not seam concerned at all.  I can't help but be a paranoid first time mommy though. I don't think I implanted late either because I got my first bfp at the morning of 10dpo.

If you charted and know about when you ovulated did your baby ever measure a little behind in first tri?  THANK YOU!