I don’t mean this in a mean or harsh way, but to answer the OP’s question: “Do I get less of God’s greatness if I’m not baptized?”
At one level, you do have God’s greatness because you exist and are alive, and your existence is a testimony to God’s greatness.
At the more important level though, you have none of God’s life, because you have no sanctifying grace. At this point, you are God’s creature; you are not God’s child. This is not an awful or terrible thing to say, although it’s blunt, but all of us went through this stage. We were all born dead, without God’s life in us.
To answer your other questions: even though you feel you have a relationship with God, it’s only that between a Creator and creature, albeit, with a Creator who loves you very much. It’s not the relationship of adoption that makes you God’s child. It’s also impossible to please God without sanctifying grace.
So does that mean, however, that you are offending God by praying? Not in the least. Because God is good and merciful, these feelings and movements you have are clearly promptings brought about by actual grace—undeserved aids and helps that move you toward forming that familial relationship with God. So keep it up; keep praying and doing good because although by themselves, cannot save you, God is clearly rewarding you with the movement of his Holy Spirit towards baptism.
When you are baptized, keep in mind that you enter the water a dead creature, just as Jesus was placed dead in the tomb. But when you arise, you are a new creation; and you are just as resurrected as Jesus was when he rose from the tomb. Your baptism will be the occasion of a great miracle, while veiled from human eyes, is no less great than the miracles wrought by Jesus when he still walked among us. For those of us who were baptized as infants, it’s something we will never perceive. You, on the other hand have a wonderful opportunity to relish this for the rest of your life.