Don't worry; God is happy when we pray, and I want to assure you that He not only hears your prayers but He is delighted when you pray. The Bible says, "The Lord ... delights in those whose ways are blameless" (Proverbs 11:20) and that's true no matter how young or old we are.
I'm glad your parents pray and thank God for their food before every meal and I'm thankful they let you participate. Everything we need in life comes from God (including our food), and it's good to stop and thank Him for it. He loves us and knows our needs, and He takes care of us. Someday I hope you'll memorize the 23rd Psalm, which begins with these words: "The Lord is my shepherd, I shall not be in want" (Psalm 23:1).
I hope you'll also thank God, however, for an even greater gift and that is Jesus. Jesus came down from heaven and was born as a baby just as you were. He grew up in a godly family, and one day He began telling people about God's plan of salvation. God was with Him in a special way (in fact, He was God's only Son), and as a man He gave His life for our sins.
He did this because He loves us, and He wants us to be part of His family forever. How can you be part of His family? Simply ask Jesus to come into your life and tell Him you want to follow Him. I hope you will pray and ask Jesus into your heart today. It's the most important decision you will ever make.