Yes, it matters. Early-on is when your baby is forming, so it is the worst time to raise your body temp like that. I would stop right away, until you find out for sure. The rays are harmful, and chemicals are going into your bloodstream from it. Sorry, I know that is probably not what you were looking to hear. I have read that tanning at any time during pregnancy is a no-no, but other ladies may have other opinions.
I have learned that I can keep going long after I can't.