Excited and Nervous

38 and just got my first positive ever.   We have been trying for awhile now and I was starting to think I couldn't get pregnant.  We had been hesistating on going in to discuss fertility treatments for the last 6 months, but had just decided to make an appointment and then this happened naturally.   I'm scared that it is too good to be true.   I'm only 11 or 12 days past ovulation, so I'm worried it will go away.  I would cry from joy, but I'm still in shock.