"But everyone's done those sins!"
Imagine if a police officer pulls you over for speeding and you say to him, "Officer, I know I was speeding, but everyone has sped in their life, can't you just let me go?" It won't work.
Same thing in the sight of God. Even if everyone has done a variety of sins, God's law has still been broken and therefore the just God of the universe must punish those that do wrong.
That's why we need someone who hasn't done anything wrong who would be willing to take our punishment on our behalf - Jesus. He offers to do that for us as a gift. We simply need to accept that gift by trusting he has done it for us on the cross 2000 years ago.
If Jesus takes the punishment for all your sins, where then will you go when you die? It's such good news, isn't it?
Related Questions:
How do I respond to "What if my good deeds outweigh my bad deeds"?