This kind of money in fiqh is called maal (money of) ad-Dimar مال الضِّمَارِ, which is money which the legal owner has no right over it or no possibility to use it -a certain time- (for example let's say you had left some money in a Bank in Australia, but have no access to it because you are actually living in Ethiopia) it was also translated Debt deemed uncollectable.
Fiqh views
The fiqh views differ here to three different views:
The hanafis, one of two opinions of the hanbalis and a less known view in the shafi'i school of fiqh is saying there's no zakat on it. Because of a Saying of 'Ali ibn abi Talib:
ليس في مال الضمار زكاة
(my own translation take it carefully)
There's no zakat on money of ad-Dimar.
due to the fact that one didn't have access to it.
The malikis hold the opinion that one is asked to pay the zakat once, after having access to it:
Yahya related to me from Malik from Ayyub ibn Abi Tamima as- Sakhtayani that Umar ibn Abd al-Aziz, when writing about wealth that one of his governors had collected unjustly, ordered it to be returned to its owner and zakat to be taken from it for the years that had passed. Then shortly afterwards he revised his order with a message that zakat should only be taken from it once, since it was not wealth in hand. (al-Muwatta')
- While the other view of the hanbalis and the stronger view of the shafi'is is that one needs to pay zakat for all the passed years once one has recaptured the money.
This is also covered in the fatwas (both in Arabic) islamweb #29749 where they seem to consider the second opinion as the strongest and also in islamqa #258935.
Implication in your described situation
This means when you got the money according the maliki view you should have paid zakat for once, according the stronger view of the shafi'i school once for each passed year.
A year after receiving the money (as described in your question) that would mean paying the zakat once according the hanafi view, twice according the maliki view, passed years (since maturity سن البلوغ) + 1 according the shafi'i view. (Shafi'i view means the stronger of both opinion).
Note that hanafis differ from the majority and say a non-mukallaf doesn't have to pay zakat (so even his waly or father don't have to) (see islamqa #75307)
Note that I assume that your father never paid zakat on behalf of this money. Usually the waly (in your case) of a young boy is asked to pay the zakat of the money on behalf his children if this reaches an-Nisab. So basically a non-Mukallaf (non-mature according shari'a) doesn't pay zakat.
Also check calculation of zakat (Wikipedia).
How to:
Let's assume (shafi'i view) you became mature and the money reached the nisab (and a lunar year passed) on (MM/DD/YYYY) 08/08/2015 then you need to pay 2,5% of the amount which was on your account at that time (to be more correct you should subtract the paid amount from the amount you'll pay zakat from the following year), and 2,5% of the amount one lunar year (~354 days) later (07/29/2016)and so on (about 07/18/2017, 07/07/2018).
In the hanafi view you may only pay 2,5% of the amount that you've got one year ago.
In the maliki view you will pay the zakat for the "years" 2017 and 2018.