Answered by Shaykh Abdurrahman ibn Yusuf Mangera
A young girl whose father is a non-practicing Tunisian Muslim has asked me to help her learn the deen and begin to pray, alhamdulillah. I have several questions:
Assalamu alaykum
In the name of Allah, the inspirer of truth
1. It is necessary for one to recognize and understand their faith after becoming adult and physically mature. They can no longer be taken as subordinate to their parents, since they now become responsible adults in Islam.
If the girl had no idea of what it is to be a Muslim, for instance, she was ignorant of the basic tenets of faith like believing in Allah, the Messengers, angels, life after death, and destiny being from Allah, then she would not have been considered a Muslim. As such she should recite the shahada again and start afresh. She does not have to make up any prayers missed before her discovery of true Islam in this case.
If she did possess basic knowledge and belief from before, then there is still no problem with saying the shahada again and renewing the faith, but she would have to makeup all the prayers missed [after maturity] from the time she gained her basic knowledge of Islam and began to believe in it.
2. I would encourage that she take a madhhab to which she has sufficient access. There is no point in following a school from which one cannot find answers for their everyday needs due to lack of resource. If the online source can provide sufficient guidance then it would be appropriate to adopt that school, however, it is easier to take up a school that one can see being practiced around them, rather than what one derived through reading only.
And Allah knows best.
Wassalam
Abdurrahman