This is a beautiful and insightful article serenity
I much agree with all what you said, and while some that are strongly religious might disagree with you about loving yourself before God, I feel and think the same way about that as you.
Even when a man or woman doesn't have a "significant other" in there life, there's always the love one has for family, friends, nature, old people, and much more. One's life doesn't fall apart nor is it less just because one isn't in a relationship. We have many relationships and love to offer other people.
I know though that it's difficult to get a young person to understand that! Hopefully all the love, understanding, and education your daughter has had will be her guide through this.