Either my youngest is ASD or super bright or both, but either way I can't cope!

[Wills]

She's my fourth and quite literally rules the entire house. She can be incredibly cold and thoughtless but at only 3 and half that could be seen by many as normal. She would give miss Piggy a run for her money in terms of being precocious! She uses screaming tatics to get her own way and can go on for hours! Being my fourth I'd have thought I'd have been better able to deal with her! Especially as my oldest is ASD and at a wonderful special school and my third is currently undergoing diagnosis. They've not exactly been a walkover either but my youngest has breaking me. I haven't felt like I'm feeling since I was struggling with post natal depression after my first was born. My fourth is so clever and seems able to permanently manipulate situations to her benefit. There are times when I'm absolutely adament that she's ASD, then she turns around and can be so caring that I'm questioning myself again. I feel a little like I'm going mad!

She sounds rather NT, tbh, which can be a shock to the system if you have children with SN.

My first has complex SN and goes to special school
My second has...well we're not sure..but something and definitely has some sort of language issue.
My third runs rings around me and is exactly how you describe - she's frightening, but NT.

I don't disagree. She's so calculating that that would be odd with ASD. I love your description of your second. My son (third) is similar, all agree not standard we just can't agree what.

Going back to my youngest, she watches every single thing we do. She'd mastered opening the front door at 18 months and kitchen cupboards were a walk in the park! Neither of which suggests SN, however my oldest has always had issues with understanding that she's a child and not equal to all other adults. I live in fear of her going through her later teens and encountering the police etc as she has no awareness of authority. This also describes my youngest. She really doesn't seem to conceive that she's a child - far more than just being a stroppy 3 year old.

My step father is very strict and most of the grandchildren (including my other 3) are wary of him. He told her no 3 times last week, each time getting firmer and louder. In the end she went over to my eldest's horse whip, picked it up and went back and whipped him. She was put in time out. It took her over 90 minutes to agree (v. reluctantly) to say sorry. She just has no fear of any adults.

Yeah, DD3 can be similar. She had her first visit to big school last week. Her new teacher invited her to colour her learning journal. When she'd copied the letters, her teacher said 'ooh why don't you draw some lovely flowers?'. She said 'I don't want to draw flowers.' No intimidation, then!

I have 2 Dd's with Asd and one without. Dd2 who is allegedly my NT one was easily the hardest work at 3!!

She used to tell me what she would wear and what she wouldnt. She wouldnt stay in bed. She could sulk for hours to try to get her own way.

She is 17 now and absolutely lovely, she still knows what she wants and can still be a little sulky but generally she is fab.

At 3 though gee whizz she was hell on legs