Doubt About Fasts

Asalamu alaikum warahmatullahi wabarakatuhu

I have a doubt regarding fasting. I used to live in the middle East and was born there. I was brought up in a Muslim household that practiced prayer, fasting, everything even quran. But once I became 10 years old we shifted from the middle East to India. Once we came here everyone stopped practicing including myself and I stopped cause no one would tell me what to do and was more preoccupied with school and what not with no guidance

Once I became 16 years old, I started practicing and found the love for islam again but that year I didn't fast . Rest of the years I fasted and am now going to be 20 on the next year and will do the next ramadan

So my question is do I have to make up all the fasts that I missed when I was younger or do I have to only make up the fast I missed that year?