KVPY bhi nahi Diya bro? @Soumyadeep
Yeah, you can attempt KVPY again, but only if you take admission in BSc, like IISER.
As far as olympiads are concerned, there is an age limit, so you can't give it after 12th. Look at me, I had no idea about NSEJS in 9th, so gave it aisehi. In class 10th, I couldn't give it because I'm 2000 born. Age limit. Lol
You haven't missed anything bro chill. In fact now just focus on JEE. Sometimes olympiads come in the way of JEE preparation. In college you'll get tons of opportunities. Tab sab Kar Lena.