Sole Child Custody ??

I have a question regarding child custody in Colorado. I know this is a stretch to ask here but I had no one else to ask and I’m not sure how to move forward in with this process through court. My question is if my the father of my child is willing to give me sole child custody will the court “allow” that or “grant” me that? We were never married. Both of our names are on her birth certificate. He doesn’t watch her at all. I’m her primary caretaker. I do let his family see her because I didn’t want her to be away from her grandma on his side and didn’t want to be “petty” That has nothing to do him though. During her stay with her grandparents , she’s there Thursday night through Sunday night but he is not the one watching her or providing for her. I have screenshots of him saying that he will just give me full custody of her when we go to court but how does that all work?