"Does life become "easier" as you age in terms of triggers and meltdowns? "
I think that people's sensitivities can change. But they can get better or worse. Puberty and menopause cause changes.
Two small examples:
I screamed blue bloody murder at having my hair touched as a child. These days I actually like it from DH, and can push through a haircut every six months from a stranger.
As a child I used to be okay-ish in hot weather. I got grumpy and didn't like it and was a terror but I didn't throw up and cry for hours, now I increasingly do which is awful.
Overall though you learn to avoid things. I live life actively hiding and avoiding stuff I don't like. I carry earplugs and noise reducing headphones and cooling towels and lots of other things around to help.
"When you were younger, is there anyway your mum (or primary caregiver) helped you or could have helped you?"
Believing me and not making me think I was going mad would have been incredible. In fairness, neither of us knew I was autistic, and she's probably on the spectrum too and had a hard time parenting.
"Do sounds hurt you physically aswell?"
Yes they can. It's horrible. Why a body would do this I have no idea! You know the fingernails on a blackboard thing? It's a bit like that.
Some noises cause rage too, I think it's known as misophonia but again, what demented twist of nature led to that?!