I am so sorry to hear this. It sounds like he is not serious. If he was, he changed his mind. You are still young and from you wanting to share with your mom that shows you are considerate and respectful as well. Be with someone that will accept you and all that comes with you including your family. Family blood is thicker always remember that. Mom has your back. If he is not ready to meet mom, he may be hiding something that your mom will pick up and share with you.