(((((Hugs)))))
My son was diagnosed about 8 months ago with mild pdd-nos. My girls were just diagnosed in July with severe speech and language delays.
Honestly - I'm still angry and sad about it.
I imagine, over time, It will get easier. Be proud for getting your kids the help they need.

I gave my older son his vaccines late so I was SURE it was them - lil bro has had none - no vaccines - (I hope I don't upset ppl with that, I'm just delaying it a lil). So that theory was blown away for us. He doesn't have regressions like his bro does but they are at the same place on the spectrum more or less.
Sorry you are having to deal with this. Often nt siblings show autisitc traits so let's just hope it's that.
My son started sensory seeking around his third b'day. His development had been fine except for speech but he was bi-ligual (theoreticaly). Afer his third b'day he showed more autistic behaviors and his develpment changed. He didn't get a pdd dx til he was 5. When I took his little bro at 2 with some concerns (he flapped hands when excited and had speach delay), they dx him on the spot becase of his bros history, but i have to renew his dx every year. Looks like he's hanging on to the dx tho, he's 4.7 now.
I'm not complaining, I was then, but I'm def not complaining now
Anyway good luck - let us know how the evals go.
I am of the thought that it is the vaccines, but i'm no expert, just a mom. I thought my ds #2 was fairly NT outside of his early speech delay. Well, a few months ago he stated these sensory seeking behaviors (putting others hands on his face and rubbing on them, licking nonfood items and his arm, putting hands over ears and tapping). He also recently started stiffening up and putting his hands about 6 inches from his face when excited. He is pretty verbal and probably, speechwise, mainly has more of an articulation concern.
Sorry you have to be going through this...I hope you get some answers soon.
As far as when sensory starts showing up, I'm not quite sure what is typical, Mason has always seemed to have them, but I can tell you that they seem to get better and then all of a sudden they show up again or new ones emerge.
Take care and hugs.
With some kids, the autistic symptoms are obvious right away. With others, they don't become obvious until they get older and the demands on them increase. For my son, his differences became obvious in his last year of pre-school. For other kids, they don't become obvious until even later.
Having 3 kids with delays is a lot to cope with. Hang in there.
Thank you all. You are all so sweet.
I have heard enough now about late symptoms coming in over 3 years old that I believe it can be normal..makes us parents nuts thinking they are out of the woods so to speak sensory wise and then boom all these things become adversive to them...
Aspergers normally get diagnosed much later than the rest of the spectrum~my cousin was 12 when he got diagnosed..he had shadow sx his whole life but not enough to validate a diagnoses..but now all those shadows has all caught up with him since he has entered middle school..it would of been much better for him if he was much younger.
Do the evaluations and get your answers...you will feel much better..all that energy is rough when it is used on worrying yourself sick..conserve it:) Slow and steady wins this race!
Wish you the best and please keep us updated!
Blessings,