My son was/is like that but is currently opening up to people. I had to tell people to keep a distance and let him be the one to go to them, he eventually opened up after a little while. Where he would cry is if a person tried to push the intial greeting. Give it some time.
It can be normal, but in our case for my son. He had a sensory disorder. You can always ask for an evaluation, sensory seeking doesn’t mean autism by the way a lot of people think it does. We all have sensory issues! The best thing to do is if he is uncomfortable maybe move him away from all the chaos & then go back in a couple minutes.
My 2 yr old daughter does that too 🥺
I think just going around people more will help eventually. My son gets shy when around people. But if we are there long enough he’ll open up.