symbolism and irony

I saw this movie over 30 years ago, and although I haven't seen it since, I remember a fair amount about it because of the effect it had on me at the time. I'm surprised that there has been no discussion of the obvious irony in the film. Here you have Natalie, running away from her life and the enormous responsibility of having/raising a child looming, and she ends up getting involved with a "child" in Caan's character. The responsibility of looking after someone that she is trying to escape is forced upon her. Did she finally come to grips with this responsibility, or did she fail? I don't remember enough about the ending to recall...