When you're learning to play the piano or electric keyboard, knowing what the lines and spaces on a staff represent and how the notes on your instrument correspond to those on sheet music isn't enough to become a proficient musician. Although you're a beginner, you can improve your abilities in many ways. You don't only need to know the correct keys to press and when to play them. A vast world of music theory and compositional variety greatly changes certain aspects of a song and ways to craft and play musical pieces to express yourself more freely.
Having the knowledge to reproduce what you read on sheet music is a wonderful skill, but music isn't about rigidly following directions. Every composer and musician should develop their style and form. You can hand a piece of sheet music to a dozen talented piano players, and each will perform it uniquely. The song's structure is the same, but there will be little techniques and flourishes that set them apart from the others. How music feels when you play is as important as hitting the right notes in the correct order.