First future mom question

I found yesterday that I am pregnant with almost two weeks!!

I read this morning that I should take folic acid three months before planning a pregnancy... I didn't because we weren't planning a baby, I also read that I need to take folic acid during the first months of pregnancy, my question is if I can just buy folic acid in the pharmacy and start taking or wait until I go to the doctor, my husband said that I don't need to go now, but I'm sure that I should go very soon, Tuesday I had X-Ray on my mouth and the next day I found that I was pregnant, that's another reason that I want to go to the doctor soon.

How bad is that I'm not taking folic acid right now??

The X-Ray will affect the baby?

I'm going to be a mom for the first time and I have a lot of questions.