So what, we will launch a massive retaliatory strike the moment our satellites observe their launch.Not to mention the fact that we have now 2nd strike capability in our arsenal thanks to the Arihant class subs,so Pakistan won't be able to survive even if they strike us first because our nuclear subs will ensure a definitive and massive 2nd strike against Pakistan.
Plus the most important factor in this scenario is the 2-Tier BMD developed by the DRDO which will definitely neutralize most of their missiles thus leaving us with the opportunity of a massive 2nd strike
(ohh,btw i forgot to mention about the David''s Sling which we'll soon purchase from Israel to complete our 3-Tier BMD).