Is the flow of blood a prerequisite for it to be considered menstruation, given that a dark color unaccompanied by anything else appeared after puberty and the questioner did not fast because of it?

What the questioner saw is not considered menstruation according to Sharia, and therefore, it does not signify puberty nor does it obligate fasting, because it occurred only once, unlike the view of the Malikis. Accordingly, she is not required to make up the mentioned Ramadan if she did not observe another sign of puberty, although it is more cautious to make it up. Menstruation does not require flowing outside the vagina to be considered present; rather, it is considered present if it reaches the place that must be washed.