Can a pregnant 15-year-old get married to her 15-year-old boyfriend in California?
In CA, if either the bride or groom is under 18, in addition to having parental consent, the couple must also schedule an appointment with a counselor and then appear before a superior court judge.
A word of caution, the age of sexual consent in CA is 18. There have been several cases in CA where the state has filed charges against fathers of pregnant girls, even though the girls and the parents protested it. Does it matter that you're both under the age of sexual consent? I really don't know, though I suspect that it doesn't matter. I'd strongly advise you to talk to an attorney before you do anything else.
The issue of both partners being the same age will most definitely have a bearing on what, if any judicial action may be taken. The most likely scenario is, each will remain in the custody of their parents, with both sets of parents being required to take financial responsibility until the minors reach the age of majority. If the teen mother's parents refuse to accept that responsibility the teen mother will be made a ward of the court and placed in a foster home for her and her unborn child's welfare. Minors have legal parental rights with the birth mother automatically assuming those rights for the child. The father will need to establish paternity before asserting those rights that pertain to him.