A child never wants a sexual relationship. This is because they do not yet possess the psychological or physiological capacity to consciously and knowingly have a sexual experience. They can say to a teenager or an adult that they feel like they want to, or they might not dare say no because they want to make them happy, but the child never desires it.
When a teenager or an adult suggests a sexual act to a child, the child does not know what it is, or whether it is good or bad for them. They are too young to know about it and they cannot say yes or no to something they know nothing about. They may be curious, but this never means that they are consenting. Everything has its time: a child will discover sex with someone their own age when they are older.