Assalamualikum I'm now turning 21 girl ,I have previously neglected my duties as a Muslim and never prayed properly or fast ,I a ashamed of myself now and I want to make up for all those thing but I've missed so many I can't find the right answer of how to make up for them .please help me by telling me the right thing to do also I've heard that if you offer a salat in medina its equal to thousand of prayers not that I want to be lazy but could that be an option?

Jhazzakaalah

Wa `aleikumus-Salaam.
The strongest opinion I think is that you cannot actually ever make up for either of them. Some imams say you have to pray all those salaat you`ve missed again. It doesn`t sound reasonable, as the Messenger of Allaah -sAaws- has warned against going to extremes in worship, because it`s better that you do what you can keep, than to overload yourself and then give up.
You have to repent to Allaah a lot. You should pray nawaafil often, because there is the Hadiith the on the Day of Judgement it will be said when a person is not coming with full record of obligatory prayers to Allaah in the near meaning that "see if there are in his optional prayers what can compensate for it". Especially in Ramadhan your optional salaat equals fardh salaat in other times according to Hadiith, and the night of al-qadr that is one of the nights in the last ten of Ramadhaan equals 1000 months according to Quran. And the Hadiith about the three Holy Mosques in Makkah, Madinah and Jerusalem, then they equal 100 000, 10 000, and 1000 salaat in other than them. Of course our beloved Prophet -sAaws- has told us these things that we would make effort to come closer to Allaah, and that we would utilize these opportunities, so it`s not about being lazy. These are gifts from Allaahs mercy that He has made many ways easy for those who seek His forgiveness and the way to Him, but the key is knowledge.
And Allaah knows best.
I`m giving you an address of a website that you can benefit so much from when it comes to your Religion, because these are all maa shaa Allaah good `ulamaa and students of knowledge giving nice audio-lectures, many languages.. so much. Try to start from eman - from tawheed. May Allaah accept from us and you our sincere repentance, and our turning to Him.
Salaam.
http://www.islamhouse.com