Praise be to Allaah.
Firstly: her Hajj is valid, in sha Allaah, but her
travelling without a mahram is something that is forbidden, as it disobeys
the words of the Messenger (peace
and blessings of Allaah be upon him): “A woman should not travel
except with a mahram.” This lady travelled without a mahram. If
she was unaware of this ruling, then I hope that she will be excused,
and she has to seek the forgiveness of Allaah. If she was aware of it,
then she has to repent and seek the forgiveness of Allaah.
But there is another question to be asked, which is:
does this Hajj count as the obligatory Hajj required in Islam?
If she had reached the age of puberty when she did
that Hajj, then it does count as the obligatory Hajj required in Islam,
even if she went without a mahram. If she had not yet reached the age
of puberty, then she has to go for Hajj again, and her first Hajj will
count as naafilah (supererogatory). What is meant by puberty is the
appearance of one of the signs of puberty, such as the onset of menstruation,
the growth of body hair (in the armpits and pubic area), or “wet
dreams” (following which one detects the emission of fluid from
the private parts). It is most likely that a woman of fourteen years
of age had reached puberty.
And Allaah knows best.