I had to find out. I like to be able to plan and I'm not big on surprises. And I just couldn't wait. I found out with both ds and dd (who is still cooking). I'm glad I found out with both of them. I found it helped me bond with them while I'm pregnant. With dd we have been able to choose her name and start calling her that. Now we say to ds, where is Emily, he comes over puts my shirt up and gives it a pat, hug or kiss. Its very cute.
I think you need to decide what YOU want and what you feel happy doing!!!