100% 14-16 for ds. Very angry young man, big enough to be very scary, & I was the only parent in sight to take it all out on.
He's nearly 18 now & mostly lovely, but I had quite a few dark nights when I seriously contemplated telling him to fuck off to his dad's, then. I resisted because I knew that would be the end of his academic potential - he's super bright but dyspraxic & highly disorganised. He'd have had a lovely couple of years playing GTA with my ex, but forget any idea of post 16 qualifications in those circumstances.
I can absolutely say that I tolerated verbal abuse, pushing me around physically on occasion, & appalling entitlement, whilst living in squalor in his room, to an extent where if he'd been a dp not a ds he'd have been yeeted into the bloody sun.
He was such a delightful baby & toddler, too!
With his sisters, it's definitely been age 11-14. Friendship dramas & general misery. Nothing to equate to ds's behaviour.
Although I did not love 2020, when all 3 dc's various crises coincided with lockdown. & my menopause. That was fun times.
It (mostly) feels that we're all OK now, but strewth, I wouldn't want to go through any of that again.