She recently became Muslim and is asking about a guardian for marriage
Question

I am the daughter of a Christian mother and father. I was born as a Christian, but – praise be to Allah – I declared my Islam a while ago. My mother is deceased, and she was Christian. My father treats me very harshly and has disowned me unofficially, because I declared my Islam. Now I am studying at a university, and I live with Christian students. I have not started to wear hijab until now, because of my difficult situation. Is this haraam? I also want to ask: if a young man asks me to marry him in accordance with the way of Allah and His Messenger, is it permissible for me to ask a Muslim family to act as my guardian for marriage and other matters?
Praise be to Allah.We praise Allah, may He be exalted, for guiding you to Islam and opening your heart to faith, and we ask Him to make you steadfast and to guide you in all your religious and worldly affairs.
Hijab is obligatory for every Muslim woman, so strive to wear it to the best of your ability, even if that is outside the university.
In order for the marriage contract to be valid, it should be done by the woman’s guardian, who is her father, then her grandfather, then her brother and other male relatives, on condition that they are Muslim. If a woman does not have a Muslim guardian, then the Muslim qaadi (judge) should do her marriage contract. If there is no Muslim judge, then the imam of the Islamic centre or a similar figure who is held in high esteem among the Muslims may do it. If there is no such person, then any Muslim man may do the marriage contract for her (acting as her guardian).
For more information, please see the answer to question no. 48992 .
To sum up: with regard to your marriage, the one who may act as your guardian in your case is the director of the Islamic centre, or a public figure among the Muslims who is held in high esteem where you are. If that is not possible, then a Muslim man of good character may fill that role, from the family whom you mentioned or otherwise.
With regard to your hijab, strive hard to observe it to the best of your ability, and whatever you are unable to do, Allah will pardon you for it by His grace and kindness, for Allah does not burden a soul with more than it can bear. But try hard to change the situation that is preventing you from practising your religion openly.
We ask Allah to bless you with a righteous husband and righteous offspring.
And Allah knows best.