Well she's definitely not dying. And that does look like powdery mildew on the last leaf. Look into h202 solution foliar spraying. Should keep it from progressing too badly if religious about it.
If your first grows went smooth sailing you wouldn't learn anything.
In the future def put into a large lr container or the ground if seems like the plant will get bigger like this.
You will have some yellow older leaves get zapped and fall away as you go through flower on an older plant too. Especially if she's been hungry and just got fed, some older leaves will go ahead and zap real quick as the higher up growth gets refreshed with nitrogen and stuff. But some yellowing away leaves is normal getting into flower most of the time.
When I see a budding out plant outside that has perfect leaves and no insect damage, I immediately raise an eyebrow. I made most of the only show the nicer pictures that I take of my patch. But I get yellow leaves that fall away and I need to remove here an there most days now. And there's some grasshopper damage and beetle damage here and there. If you look close youll find some old mite/aphid scabs here and there. There's no such thing as an outdoor plant that makes it to the finish line with no Battle scars.
And like I said if your first grows went perfectly you wouldn't learn anything lol. She may be a little rough around the edges but I see no reason that you wouldn't be able to get smokable harvest off that plant by finish
it's not ideal, but you can even wash away most of the powdery mildew from flowers that are infected at harvest. And they're still worth smoking lol
