Yes, what you've heard is true; God is concerned about every detail of our lives. It's true not only because God knows everything, but also because He loves us and wants us to experience what is best for us.
Think of it this way. As a parent, you love your children -- and because you love them, aren't you concerned about every detail of their lives? They don't know what's best for them when they're young -- but you do, and you want to guide them in the right way. Parents who don't care what their children are doing (or failing to do) not only endanger their lives, but don't really love them.
In a far greater way, God is our loving Heavenly Father -- and He knows what's best for us. That's why we can turn to Him and ask Him to guide us when we have decisions to make -- and we should, because we easily go astray. Jesus said, "If you, then, though you are evil, know how to give good gifts to your children, how much more will your Father in heaven give good gifts to those who ask him!" (Matthew 7:11).
Accept the gift of God's love into your life, by inviting Jesus Christ to come into your heart. Then ask God to give you wisdom in everything you do -- and He will, as you seek His will in prayer and make the Bible part of your life every day. Remember: "Nothing in all creation is hidden from God's sight" (Hebrews 4:13).