Inshaallah on your effort. Allah put you on the right path. Be grateful for that.
About your question, yes you need to pray and fast for those days, but don't worry. It's not that much hard. For example, I do one day Qadha pray everyday, so after two years and half from now I'll be done with Qadha prays. You can also come up with a program for Qadha fasts as well.
Here are two posts for Qadha prays and fasts:
Keep going brother
Brother, offer thanks to Allah & instead of inventing questions like these, ask Him to grant you the steadfastness on deen.
Surah Al-Maeda, Verse 54:
يَا أَيُّهَا الَّذِينَ آمَنُوا مَن يَرْتَدَّ مِنكُمْ عَن دِينِهِ فَسَوْفَ يَأْتِي اللَّهُ بِقَوْمٍ يُحِبُّهُمْ وَيُحِبُّونَهُ أَذِلَّةٍ عَلَى الْمُؤْمِنِينَ أَعِزَّةٍ عَلَى الْكَافِرِينَ يُجَاهِدُونَ فِي سَبِيلِ اللَّهِ وَلَا يَخَافُونَ لَوْمَةَ لَائِمٍ ذَٰلِكَ فَضْلُ اللَّهِ يُؤْتِيهِ مَن يَشَاءُ وَاللَّهُ وَاسِعٌ عَلِيمٌ
O you who believe! whoever from among you turns back from his religion, then Allah will bring a people, He shall love them and they shall love Him, lowly before the believers, mighty against the unbelievers, they shall strive hard in Allah's way and shall not fear the censure of any censurer; this is Allah's Face, He gives it to whom He pleases, and Allah is Ample-giving, Knowing.
(English - Shakir)
Surah Muhammad, Verse 25:
إِنَّ الَّذِينَ ارْتَدُّوا عَلَىٰ أَدْبَارِهِم مِّن بَعْدِ مَا تَبَيَّنَ لَهُمُ الْهُدَى الشَّيْطَانُ سَوَّلَ لَهُمْ وَأَمْلَىٰ لَهُمْ
Surely (as for) those who return on their backs after that guidance has become manifest to them, the Shaitan has made it a light matter to them; and He gives them respite.
(English - Shakir)
Try to take benifits from the blessed nights like shab e qadr, shab e bara'at, last friday night & day of Ramadhan. They will makeup your account & removes your burden In-sha Allah.
And no, its not too late. A true & sincere repentence is all what one need for his success before death approaches him.
Just try to offer obligatory prayers with sunnah & salat al layl regularly from now onwards. And try to use the blessed nights.
Dont worry, put your trust on Allah. He is the Most Merciful.
Learning is a continuous process which never ends. We even learn something from our own death.
You're Alhamdolillah alive, start your journey with prayer "Rabbi zidni ilma".
Great quotation from the FT today.
1. an undemocratic putsch is now defined as being 'popularly backed' making a weak attempt at legitimising it
2. the previous democratically elected government is now disparaged by simply being labelled Islamist.
Black is white and white is black.
For argument sake, let's take your word. Your world is Data. observation, tangible stuff. Based on all the date you have collected. Let's not waste time finding a Common animal ancestor,( you can spend the time and energy, if you like), its of no consequence, but lets see from what you have from " Science" what does it tell you, how a human should live his/her life.Otherwise all the technical stuff is only good for toasters, microwave, cars and jets and new buildings...starwars or some corporation mining the material form a an asteroid or looking for aliens ...
What can Humanity benefit from these findings...Are you willing to live by the Data, Observations form the Natural world and their conclusions.