Johnston shared her story with the Rotorua Daily Post in the lead-up to World Autism Day on Tuesday.
"I always knew there was something a little bit different about how Bailey showed up in the world," Johnston said.
"He would have fixations for a period of time and then he would flick off to something else.
"We couldn't take his Spiderman outfit off him, he would scream blue murder. So we let him sleep in it and would try to take it off him while he was asleep. Then we could wash it and give him it to wear it the next day."
Bailey spends most of his time at home, hanging out with his mum.
"We've tried a couple of different schools ... but he found it really challenging to have me leave.
"He did the first few days of school this year and he did really well because his dad was with him. A lot of autistic people have their one person where they understand each other.
"But then, of course, his dad had to get back to work so I was taking him."
Johnston said some days were easy but equally some were challenging.
She said often autistic children didn't show their love like a "neurotypical kid" might and as a parent, it was hard waiting for "I love you mummy" to escape their lips.
Johnston decided to train as a parent coach because she saw the lack of support for other parents like herself and now ensures they understand it's not the behaviour to focus on, but the need underneath it.
"I think people are really trying to make their awareness grow but society as a whole still thinks a child having a meltdown is a naughty child.
"You can't judge the parent who is dealing with that meltdown because you don't know what has led up to the moment."
She said instead of making a nasty comment, criticising, or even making faces while walking past offer up some compassion by asking if they were okay.
Meg O'Dwyer's two daughters aged 5 and 7 are both autistic and "came out brilliant and stayed that way".
"My life is different, it is not forming to a conventional norm but, there is no need to pity me or my kids.
"But some understanding that things could be different would be great."
O'Dwyer knows she will have put her life on hold for at least the next 15 years to care for them both but said thanks to Mountain View Preschool and the Ministry of Education her daughters felt comfortable outside of their home environment.
"They both have high levels of intelligence, they just get overwhelmed in their environment and it is not their fault.
"I wouldn't change my kids for the world, but I would change the world for my kids."
A stand to raise awareness on World Autism Day will pop up at City Focus next Tuesday. It will feature raffle tickets and information.
Rotorua's Altogether Autism co-ordinator Breanna Turner said challenging language was one step forward to becoming inclusive.
"They are quite capable and in some cases more capable than us because they can figure things out really quick.
"If you don't get subjected to it then sometimes you won't believe which is why we want to be out there and in people's faces ... and bring down the barriers."
What is autism?
• A neurodevelopmental condition that affects cognitive, sensory, and social processing
• Estimated to be present in one in 59 people
• Characterised differently in different people but most experience difficulty with social skills and have different sensory needs
• May insist on routine or be hyper or hypo reactive to sensory input
Source: Autism New Zealand
