A girl is not sure whether she is to be attributed to her father

In His holy Book, Allah instructs us not
to enquire too deeply into matters that have nothing to do with our deeds
and which, if the truth became plain to a person, may cause him trouble.
Allah, may He be exalted, says (interpretation of the meaning):

“O you who believe! Ask not about
things which, if made plain to you, may cause you trouble. But if you ask
about them while the Quran is being revealed, they will be made plain to
you. Allah has forgiven that, and Allah is Oft-Forgiving, Most Forbearing”

[al-Maa’idah 5:101]. 

In Tafseer Ibn Katheer (3/203) it
says:

Here Allah, may He be exalted, instructs
His believing slaves and tells them not to ask about things for which there
is no benefit for them in asking and enquiring about them, because if those
matters were made plain to them, it may cause them trouble and it may be
difficult for them to hear about them. End quote. 

The commentators mentioned as the reason
for revelation of this verse a situation that is similar to your situation
that you are asking about. One of the Sahaabah was uncertain about his
attribution to his father, and he wanted to find out about that by asking
the Prophet (blessings and peace of Allah be upon him). But when he asked
him, and the Prophet (blessings and peace of Allah be upon him) answered his
question, Qur’an was revealed criticising this behaviour on the part of that
questioner and rebuking him for enquiring into such matters. Al-Bukhaari
(7089) and Muslim (2359) narrated that Anas (may Allah be pleased with him)
said: (The people) asked the Prophet (blessings and peace of Allah be upon
him) until he was hard pressed by their questioning. He ascended the minbar
one day, and said: “You will not ask me anything but I will explain it to
you.” I started to look to my right and my left, and every man had wrapped
his head in his garment and was weeping. A man (‘Abdullah ibn Hudhaafah) who
used to be slandered and attributed to someone other than his father [i.e.,
if he had a dispute with anyone, his opponent would attribute him to someone
other than his father] stood up in the mosque and said: O Prophet of Allah,
who is my father? He said: “Your father is Hudhaafah.” 

Qataadah used to quote this hadeeth in
reference to the verse (interpretation of the meaning): “O you who
believe! Ask not about things which, if made plain to you, may cause you
trouble” [al-Maa’idah 5:101]. 

Az-Zuhri said: The mother of ‘Abdullah ibn
Hudhaafah (who was the mother of the Sahaabi who asked this question) said:
I have never seen a son more disrespectful than you. How can you be sure
that your mother did not commit some of the sins committed by the women of
the Jaahiliyyah, thus you would have exposed her before the people? 

What we advise you to do is to refrain
from mentioning this matter and from wondering and asking about it. Do not
ask your parents or anyone else about it. You are definitely to be
attributed to your father, because you were born to his wife and the
Messenger of Allah (blessings and peace of Allah be upon him) said: The
child is for the (owner of the) bed (i.e. the husband). Narrated by al-Bukhaari
(2053) and Muslim (1457).  We ask Allah to guide you and help you to do all
that is good. 

And Allah knows best.