Im sorry but I cant tell you whether your daughter should or should not get married or whether she should or should not put it off.... here in the USA if she is not a minor (under 18) then the decision is her's and hers alone. once she turned 18 that meant no one not even her parents have control over whether she gets married or not.

my suggestion since you have concerns you will need to talk with your daughter and let her decide what is best for her self....

that said if you really feel she is not capable of making her own decisions you can go to your county courthouse and petition family court system for guardianship over your daughter. you will have to show proof that she is not physically, mentally and financially able to live on her own, making her own mental and physical health decisions, right down to having her own bank account. if the courts agree with you that she can not take care of her self and her own decision making rights they will appoint someone that will be in charge of her physical and mental health decisions, where she lives and what she can and cant do with her time and money.

should you go this route of removing her decision making rights that the appointed guardian is not always the one that petitions the court, the courts will do whats best for her even if the appointed guardian turns out to be adult protective services caseworker or her appointed lawyer or a lawyer of her own choosing. the courts will do an in depth investigation of all relatives and friends and then make their decision on who and where your daughter will be with until she is mentally/physically and financially capable of making her own decisions again.