Did you start on the music this early because you were tired but had time and wanted to not code tired? or did you have like a really cool idea and so started on it early? (I guess maybe you could have gotten the core systems ahead of schedule?)
I just grabbed a guitar, pressed record and started playing without thinking about it too much. It's a chill thing to do after programming as long as you don't have any expectations for the quality of the recording. That said, it's ofc always good to have as much raw material as early as possible. It takes time for ideas to develop.