Praise be to Allaah.
Firstly:
We congratulate you for embracing Islam and we ask Allah to
make you steadfast in it and to guide your parents and your family to Islam,
for He is the Most Generous.
Secondly:
If a woman becomes Muslim but her family do not, they do not
have any guardianship or authority over her.
Ibn Qudaamah (may Allah have mercy on him) said: The kaafir
does not have any guardianship over a Muslim woman under any circumstances,
according to the consensus of the scholars, including Maalik, ash-Shaafa‘i,
Abu ‘Ubayd and ashaab ar-ra’y. Ibn al-Mundhir said: All of the scholars from
whom we acquired knowledge unanimously agreed on this.
End quote from al-Mughni, 9/377
Based on that, your father has no guardianship over you with
regard to marriage and guardianship moves to the closest of your male
relatives (‘usbah, i.e., male relatives on the father’s side, such as the
grandfather, brother or paternal uncle). If you do not have any Muslim
relatives, the director of the Islamic Centre or the imam of the mosque may
give you in marriage.
Thirdly:
If your family are not convinced about you getting married,
and you fear that getting married without their permission will result in
negative consequences, such as severing of family ties or a reaction from
your family against Islam, the imam of the mosque or the director of the
Islamic Centre may give you in marriage without your parents’ knowledge, and
you can delay the consummation, waleemah and wedding party until you are
able to convince them.
If you are not able to convince them within a short time and
you fear for yourself if you remain without a husband, then you can go ahead
with the marriage and your husband can consummate the marriage with you in
accordance with shar‘i rulings, but without your parents knowing about it.
Then if they find out about your relationship with your husband, you can
give them the impression that he is your boyfriend and so on, because the
husband is a friend of his wife, and thus you can conceal the true nature of
your situation from them.
Whenever you are able to convince them, there is nothing
wrong with repeating the marriage rituals in front of them superficially, so
as to ward off their harm from yourself or prevent them from cutting you
off.
For more information please see the answer to question no.
68752
And Allah knows best.