We had ASAT missile in our arsenal from 2012 but we conducted test only after China meddled with our RISAT satellite in 2019 to show that next time they do anything to our satellites their satellites too won't be spared....
So we always disclose our capabilities only after 5 to 10 years after we have already inducted and tested that capabilities.
Also one more thing Agni 5 is 8000kms MIRV capable missile which can hit anywhere in China and whole of Europe, Africa and Australia too. With Agni 6 we will bring the Americas too in our range.
One more thing Agni 5 and 6 are actually Surya 1 and 2 missiles which were in making from 1994 itself. So it should have been in service from 2010/12 itself. Which is when we conducted first test of Agni 5....