The rind will become harder as the seeds inside mature, along with the strings that surround them. When fully mature, the rind cannot easily be pierced with a thumbnail, and the rind color usually changes slightly, with most varieties changing to yellow or yellow-cream. You probably have another couple of weeks to wait.

spaghetti squash can be eaten at any stage, so if you want to eat it, I'd eat it.

If you want to store, wait per the above instructions.

Thanks a bunch. I have five plants growing, so hopefully I will have plenty to store for winter, even if I sample some in the meantime. So far, so good, although I'm starting to war with squash bugs on other squashes nearby.

Made a batch of marinaria sause yesterday and look forward to tasting that on some squash.