No, you're not too young to invite Jesus Christ to come into your life! And you can do it right now, by simply asking Him to come into your heart, and telling Him that you want to follow Him the rest of your life. Jesus' promise is for you: "Whoever comes to me I will never drive away" (John 6:37).
Your letter reminds me of something that happened one day to Jesus. It had been a very busy day, with large crowds gathering around Him to hear what He was saying. Many children were there also, but Jesus' disciples tried to keep them away -- perhaps thinking that Jesus wouldn't want to be bothered with them. But the Bible says He became upset at them for doing this, and told them He welcomed the children and wanted them to be His followers. He said, "Let the little children come to me, and do not hinder them, for the kingdom of God belongs to such as these" (Mark 10:14).
No matter how young or how old we are, we all need Jesus. We need His forgiveness, and we also need His presence with us every day. Sadly, many people decide they'll wait and turn to Jesus some day in the future -- but they keep on delaying, and for them that day never arrives. Don't let this happen to you.
As a footnote, I suggest you ask your parents to visit your local Christian bookstore to find a Bible story book (and perhaps some other books) to help you understand more about God and His love for you.