Jesus told us in John 3:3 that except a man be born again, he cannot see the kingdom of God. Jesus went on to explain the difference between being born of the flesh, and becoming born of the Spirit. Except a man is born of water, and of the Spirit, he cannot enter into the kingdom of God. Jesus makes the distinction between the fleshly birth of water to the spiritual birth of the Spirit. That concept is supported in John 6:63, whereby Jesus tells us that it is the spirit that quickeneth, the flesh profiteth nothing.
Being a Christian is not simply because your parents were one, or you walk into a church building, or do as other religions (Bud-hind-lums), where if you want to join them they tell you to see their priest or leader and he will write your name on a piece of paper. Christianity is a covenant with God (as Abraham made in the OT), this is a New Covenant with God through Jesus. Thus, when you invite Jesus into your life to be your Lord and Savior, you are in essence, making a covenant with Him.
Many say they have tried Christianity, but found it was not as they supposed. For that reason, they wind up making a covenant to bash Christianity as much as they can. All this came about because they did not keep their end of the covenant and now they place the blame upon God. What was the real reason that Christianity did not turn out as they supposed? It was simply because they made a one-sided covenant. A one-sided covenant never works. Isn't that like what some couples do when they get married - where they secretly say, "if I don't like her (or him) later, I will just divorce."
So how do we know the "Born-again" experience is real? There are no rituals or signing-up involved. Everything is done by faith and a free-will. When an individual makes a covenant relationship with God to make Jesus their Lord and Savior, that individual becomes born-again and the Spirit of God takes up residence in that person's heart. You have heard that the proof is in the puddin; in this case, the proof is in the heart. What better proof could one ask for? Do it now and prove it for yourself and ask Jesus into YOUR heart.