Very nice, I've grown several Northern Lights autos, from Nirvana before, and they slow to get ripe, fastest one was like 90days, from seed, one took 98days. Killer smoke, smelled like pineapples to us,
Some are slow to show amber an some fast, once they start showing, on the calyxes, not sugar leaves, just keep a close eye on them an you'll be fine,
Nice job.