How can I sign my baby up for medi-cal if I'm not on medi-cal?

I am currently 30wks pregnant, but because I am still a full-time student, I am covered under my mother's insurance. My boyfriend and I originally planned to insure the baby under his carrier, but he switched jobs and now wouldn't qualify for insurance for 90 days. I am pretty sure because I don't work and his income is our only income the baby will qualify for medi-cal until then, but how and when can we apple for coverage for just the baby?