I was like 4 months when I got mine. Just went to my local wic and made an app. You need proof that you're pregnant though.
I got a sheet to fill out when I delivered at the hospital for wicc and then I got a call for approval a few days later. After that they will tell you when to come in and what to bring and where to go. They should explain everything. I've heard you can sign up when pregnant but I waited cause I didn't think I needed it but now I am so happy I signed up formula is a but load of money. (I wanted to breastfeed but ended up not being able to)
Anytime is fine I sighned up about 4/5 months of being prego and they give me fruits, juices, bread, milk and other healthy stuff .
Usually you go to your local community health center or health department. And I think you can sign up now that you are pregnant.