All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
Apparently – and Allah knows best – there is no religious impediment that this girl accepts this man's marriage proposal if he is an eligible suitor for her. That other proposal (when she was born) should not be taken into consideration because it was apparently not serious (done in jest). The Prophet, sallallahu ‘alayhi wa sallam, said that there are three things only which are valid and have legal implications whether they are done seriously or in jest in the following hadeeth: Abu Hurayrah, may Allah be pleased with him, narrated that the Prophet, sallallahu ‘alayhi wa sallam, said, “There are three things which, whether undertaken seriously or in jest, are treated as serious: marriage, divorce, and taking back a wife (after a divorce which is not final).” [Abu Daawood, At-Tirmithi, and Ibn Maajah]
What happened between the girl's father and that boy was a kind of engagement, and not a marriage.
Allah knows best.