Great work on your first!
I do not hesitate to file the nodes flat, though, I know the physical properties of my bamboo so not worrying. I flatten until it perfect level with shaft and then sand and polish. The nodes are solid and strong, when I test to failure they usually hold up longer than main section. The only time it break at node was when I shot arrow and it deflect off stone which hit node causing sharp impact bend in this area.
You should test one shaft, if you can spare. These nodes look very flat, I think it will be ok if you sand them.