I'd wait to do anything with fumes (nails or hair done, painting, etc) til at least your 2nd trimester and in a very ventilated area with Dr approval. I know it sucks but during the 1st trimester it's still very risky and every little breath/bite/drink/stress effects the baby now more than ever while it's still getting developed enough to 'stick' and maintain your pregnancy... even if you are second guessing I'd always avoid it, it's temporary and not worth risking. once baby is bigger and done with all the vital development it's safer in there. good luck!
I paint furniture that I resell, there aren't any paints that are safe to be around while pregnant though latex paint is said to be okay in well ventilated areas. I would invest in a respirator, they're not too expensive. No matter how ventilated the room is, the paint fumes and solvents are not safe to breathe during pregnancy.
I just painted my nursery 2 weeks ago. Paint is typically lead free nowadays (I don't know of any retailer that still sells lead based paint) anyway so as long as you have the windows open you will be fine.
if it's very well ventilated but your still very early in your pregnancy I wouldn't risk it
i choose not to paint