Added comment: Throughout the Bible. salvation, while having a "personal experience" element to it, never-the-less remains a life-long process (to them who overcome to the end), and not a single event. The closest we have to a "single defining event" is when God places His seal upon an individual - receiving God's Spirit within - anytime after repentance.
Generally, these kinds of questions are asked by those who are not sure of their own salvation. There remains a doubt of when, where, or how their salvation was effected. So, there remains a lingering need for reassurance; that all of the necessary religious rituals were performed correctly. The only other reason of engaging is such fruitless discussions is to challenge another's perceived salvation experience. But, even this approach (justification for challenging) reveals an underlying doubt of one's own relationship with God. With that doubt comes anger and sadness.
Solution: Receive the promise of salviation by faith and move on - keeping
Hebrews 6:1-3 in mind.