One of the most terrifying attitudes to religion is "we'll find out when we die". Many use this as an excuse to delay, or even forsake critical thought regarding Christianity. It is alleged that it is impossible to know the truth from this side, and so we might as well not bother trying. Rather, if there is a God, we will know when we die.
The problem with this is that death is final. Very few people have ever been raised to life after death, and even of those few exceptions, only one of them (Jesus) is still alive. The rest of them all eventually died again. When we die, we will not have the option to come back to life and be saved. If you aren't saved before you die, you will never be saved.
The great thing about this situation, however, is that we don't actually need to wait to die. See, I don't need to visit London to know it exists. My mother has been there. If there was any doubt that London existed, I could just ask her. Other places in the world exist, and while I have not been there, nor do I know anyone who has, its existence is still well reported. The Galapagos Islands, for example. I've never been, I've never met anyone whom I know to have been, yet I am still confident that they exist.
Likewise, while I have not personally died, nor am I in direct communication with any mortal who has died, Jesus did die, and He did rise again. He has testified to not only the existence of God, but of Heaven, and of Hell, and of how to avoid the latter and inherit the former. Namely, in this life, we must repent of our sins, confess Him as Lord, and believe God raised Him from the dead. If you're waiting to die, stop waiting, because then it will be too late. Today is the day of salvation. There is no point waiting until the train has left the station to decide if you should have got on it.