I know, without a doubt, that when I kick-the-bucket, I will be with Christ in Heaven, even though I am a sinner and by rights, I should not be there.
I don't deserve to enter heaven on my own good works, I could never do enough good deeds to earn it anyway. I can't buy it either - it's not for sale.
Salvation, redemption of sins and reconciliation with God is the gift of God through Jesus Christ alone. It's open to anyone and everyone right now! That includes you reader!
If you are still trusting on your own goodness you won't make it. Relying on your own self-righteousness is going to fall pitifully short. Or are you so good that you are equal to God?
Nobody is promised tomorrow so why are you waiting for 'the right time' to get saved through Christ? The day of salvation is TODAY!
You can Know for sure that you will be in heaven one day.