Does a girl's conversation with young men during the daytime in Ramadan invalidate the fast and necessitate making up for it, knowing that she repented on the first days of Eid and was fourteen years old at the time?

Conversation between non-mahram individuals when not necessary does not invalidate the fast, nor does it require a make-up fast, as long as lust is not aroused and semen is not emitted. It is advised to keep away from non-mahram men.