Yes, that happens a lot, I think. People with BPD are usually very intelligent, creative, resourceful, etc. and quite often are able to pass through much of life struggling but not letting anyone see how they struggle. We can fall through the cracks and not be noticed. Although the patterns that end up being called BPD are established by early adulthood, it might not be diagnosed until a later age. Structure does help make it easier to hide too, so if you lose structure things get harder and the patterns emerge again.