We are holy in God's eyes because of Jesus and what He did for us, but we are still sinners. Jesus was the sinless Son of God. He lived a perfect life in our place. When He died for us he took the punishment we deserve from God for our sins, upon Himself and gave us His holiness. He paid the debt we owe to God.
We are born sinners, but God expects perfection and holiness. Jesus blood and His sacrifice on the cross covers our sins and makes us holy. That is where the saying of the song writer "we are washed in the blood of the lamb" comes from. Jesus blood makes us clean. However that doesn't give us the right to go out and do whatever we want, deliberately sinning against God. If we deliberately sin and are not sorry for it, we nullify the sacrifice of Jesus. Hebrews 10:26 tells us; " if we deliberately keep on sinning after we have received a knowledge of the truth, no sacrifice for sins is left, but only a fearful expectation of judgment..." If we truly love God and appreciate the sacrifice Jesus made for us, we will be sorry for the sins we commit and we will try to live a life that glorifies God. Out of love for God, we will love others and although it is impossible for us to be sinless, we will do the best we can and when we fail, which we will do daily, we will go to God with a contrite heart and ask His forgiveness. We do this because we love God, not to help us get to heaven. We are helpless to get to heaven on our own. Nothing we do on our own will win heaven for us. Faith in Jesus is the only way to heaven and we cannot even come to faith on our own. The Holy Spirit puts faith in our hearts through His word.
Jesus died for all people, but if we choose to reject His sacrifice and His free gift of salvation we are not covered with His holiness.
I hope this helps you to understand. If you are not sure if you have faith, pick up your Bible and begin reading. The gospels, Matthew, Mark, Luke and John are a good place to start. They are fairly easy to understand and as you read, you are opening your heart to let the Holy Spirit do His work in you. You will be blessed!
Thank you for your question. I will happily answer any further questions you might have.