Curious about behaviors in 21 month old
First I'd like to preface by saying that my interest in my son came about from researching my own potential issues, for which I intend to speak to a psychologist/psychaitrist early December to determine what those my be. Ever since I have started reading up on various potential conditions, among which was Aspergers, I wondered about my son. He is 21 months old and does not initiate words on his own. He grunts and babbles and gestures (or throws...) on his own. He will repeat some words but will not initiate the speaking. For example, if he will bring me a cup and I will ask, "Do you want juice?" and he'll hold the cup and say "Joos". He can point to various body parts, and he will generally follow instructions (i.e. "Throw that piece of paper in the trash", "Go put the cup in the sink"). He is VERY clumsy. He injures himself no less than about 10 times a day just running around, following his older sister (3 years old) or doing his own thing. A lot of the time he refuses to play with his older sisters (3 and 8). Sometimes he will but he seems to prefer to play alone, though he does seem to like "being buddies" with his younger brother (5 months) and he loves spending time with Daddy. He often has to be right up on my business, leaning into me, his arm wrapped in my arm (which sounds good but I have sensory issues so I tend to find it irritating though I try not to lol). Like right now he is sitting beside me, almost on top of me, with a wireless playstation controller pushing all the buttons. He has extreme stranger anxiety and always cries when we leave him in the church nursery even if we try to "let him go gently", and will often cry most of the time he's there. He's very leery even of family we see fairly regularly such as my mom and step dad. He will hide behind me. He has some interesting OCD-ish qualities too which I cannot find any information on from Google. For instance, he loves electronics. He always gets my iPhone, or the playstation control, or remote control and starts pushing buttons. He and my three year old recently completely disassembled two flashlights down to the little tiny lightbulbs. He REFUSES to let anyone suck their thumb. Mostly this is seen with my 5 month old who is a huge thumb sucker. Every time my 21 month old sees this he pulls his brother's thumb out of his mouth. As he doesn't vocalize he is a big hitter and biter (his two older sisters didn't really do this). At night a lot of times he'll shake his head back and forth quickly to fall asleep. I watched him one night and he did this sitting up for several minutes and then lay down and continued to do it. Whenever the family is watching tv, his siblings will be still watching and he'll be moving around - I don't know if he's dancing or what. It will happen when there's not music playing on the tv as well. Some examples of his tantrums would be if he wants juice and I tell him not right now, he'll get mad and throw the cup across the room.
He's obsessed with light switches. He is constantly turning them off and on - even yesterday at the doctor's office. He kept trying to get to the light. He hates anyone messing with his ears or nose.
So I think that's it. I don't know - he could be perfectly fine and normal for a 21 month old. The big thing that had me curious was that he doesn't talk. When I searched for information online everyone stated that their child would say a few words and mostly repeat. My son does not initiate any kind of words. He always babbles but will repeat words if someone says them first, but only as though it were the answer to a question. Like "Say Mama" will get a "Mama" response. And he can point to me if I say "Where's Mama", but he won't come to me out of the blue and say "Mama!" The only times I've seen this is when my 3 year old comes to me saying Mama and he is copying her.
I'm mostly just wondering if this sort of behavior would be worthwhile seeking out a doctor for or if I'm just overanalyzing his behavior and should wait before jumping to any conclusions.