I'd like to share a few linguistic reasons why this verse cannot be referring to prepubescent girls, it involves some basic Arabic grammar.
The verse 65:4 with the Arabic text for reference:
وَٱلَّـٰٓـِٔى يَئِسْنَ مِنَ ٱلْمَحِيضِ مِن نِّسَآئِكُمْ إِنِ
ٱرْتَبْتُمْ فَعِدَّتُهُنَّ ثَلَـٰثَةُ أَشْهُرٍ وَٱلَّـٰٓـِٔى لَمْ
يَحِضْنَ ۚ وَأُو۟لَـٰتُ ٱلْأَحْمَالِ أَجَلُهُنَّ أَن يَضَعْنَ
حَمْلَهُنَّ ۚ وَمَن يَتَّقِ ٱللَّهَ يَجْعَل لَّهُۥ مِنْ أَمْرِهِۦ
As for your women past the age of menstruation, in case you do not
know, their waiting period is three months, and those who have not
menstruated as well. As for those who are pregnant, their waiting
period ends with delivery. And whoever is mindful of Allah, He will
make their matters easy for them.
— Dr. Mustafa Khattab, the Clear
When negating using verbs (مضارع), the Quran uses four conjugations depending on the time for which negation is implied. For this answer the first two would suffice, but for sake of completion they are:
- لَمّا "Not Yet" is used in the Quran for things that have not happened but will happen in the future as seen in 62:3.
the mentioned لَمّا is followed by a present tense (مضارع), However لَمّا followed by a past tense denotes "when" and is very common in the Quran. The former only occurs around 7 times( 2:213, 3:142, 9:16, 10:8, 62:3 and 80:23)
Past Negation that includes Future Negation, "do not (and will not)" is لَمْ which is used here. Arabic uses the present tense here although the intended meaning is in the past.
The future negation, "will not" is لَنْ
Past negation, "Do not", that doesn't include the future tense, Quran uses ﻵ followed by a present tense 2:18
To summarize the meanings by tense:
|1. لَمّا (Lamma)
|2. لَمْ (Lam)
|3. لَنْ (Lan)
|4. ﻵ (Laa)
X = Negation, O = Confirmation, ? = Ambiguity or Context Dependent
The category of women mentioned as "those who have not menstruated" uses the word 2. لَمْ for negation. لَمْ when used along with the present tense means "do not" and includes "will not".
Hence it cannot, linguistically, infer to prepubescent girls. For this to happen either:
(A) 1. لَمَّا, which would have referred exclusively to prepubescent girls or
(B) 4. ﻵ, which can be extended to include them
should have occurred.
Therefore لَمْ يَحِضْنَ cannot linguistically refer to prepubescent girls. The translation simply mentions "have not" which, although satisfactory, doesn't refute the possibility of inferring said meaning.