All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
We will summarize our answer to your questions in the following:
1- The view of the majority of the scholars is that the person who forsakes the prayer, even if he totally abandons it, without denying that it is obligatory is not a Kaafir (disbeliever). This is the preferred view in many of our Fataawa. For more benefit, kindly refer to Fatwa 84235.
2- Paying the Zakah to a fortune-teller: It is not permissible to give Zakah to a Kaafir. Whoever gives Zakah to such a person is not freed from the obligation of Zakah. However, we cannot rule that that fortune-teller is a Kaafir, as long as she professes to be Muslim. We first have to examine the method she uses in fortune-telling and determine whether or not it involves major disbelief. If it does, then evidence must be established against her and we cannot judge that she has gone out of the fold of Islam before that. Indeed, not all fortune-tellers and magicians are guilty of major disbelief. Shaykh Ibn Baaz said: “As for magicians, fortune-tellers and soothsayers, it is absolutely impermissible to ask such people about anything, and it is absolutely impermissible to believe in what they say, because they are liars and dissolute people and some of them may be non-Muslims if they claim to know the unseen…” For more benefit, please refer to Fatwa 15284.
Therefore, if that fortune-teller is among the eight categories of people eligible for Zakah (clarified in Fatwa 88368), then the Zakah that was given to her has freed you from the obligation, but you should be keen in the future not to give Zakah to her.
3- Any uncertainties about the Zakah that you entrusted your mother to pay on your behalf for past years are not to be given any play. You are not required to give it again, especially as you mentioned that your mother was very keen on seeking out eligible recipients. However, if you are sure that she was negligent, then she is liable for the money spent. The jurists have stated that “when someone is entrusted to do something, he is bound to do all in his power not to cause harm to the person who entrusted him, as the Prophet said: "There shall be no harm nor reciprocal harm.” He is also obliged to do as the person who entrusted him requires, and he is bound to abide by relevant customs in general cases of power of attorney. If he violates the terms, he has trespassed and is held liable...” [End of quote from the Fiqh Encyclopedia]
4- Any uncertainties about reaching puberty before having menses are not to be given any play, because basically you had not reached puberty (until the opposite had been proven). So, if you doubt whether or not you reached puberty, then you are not required to make up for any prayers or fasting and you should not open the door to obsessive whispers, as it is a difficult door to close. However, if you are certain that you reached puberty before that – not just have doubts about it – and you do not know the exact time that happened, then you should endeavor to estimate the amount of prayers and fasting that you missed during that period. [You are only required to make up prayers and fasting according to your estimation, because] Allaah does not burden a soul to do more than it can bear. For more benefit, kindly refer to Fatwa 83431.
As regards the obligation of paying Zakah, the correct and majority opinion is that it is not a condition that one reaches puberty, because, according to the majority of scholars, the legal basis for the obligation of paying Zakah is the ownership of property itself, regardless of whether the person has reached puberty or not. If one has not reached puberty, it is his guardian who is obliged to pay the Zakah on his behalf. For more benefit, kindly refer to Fatwa 87001.
5- We did not understand what you mean by your question ‘my mom takes care of my jewelry…’. If you are asking about the ruling of giving Zakah for it, then please refer to Fataawa 87362 and 82925.
As regards a book on the rulings on Zakah, then you may read the book entitled ‘The Fiqh of Zakah’ by Shaykh Al-Qaradhaawi. It is translated into English.
Allaah Knows best.