I'm in my first TA job, started in September.
I found people ok, but my class teacher was extremely curt for the first term-ish. I work 8.30-1.30, so no lunch break, which was both a blessing and a curse - it can be quite unfriendly as people take the opportunity to check their phones, but it also meant most days I did not really talk to/ have a relationship with another adult apart from my class teacher.
Another poster above had a beautiful turn of phrase which I am shamelessly magpie-ing 'questions are met with little patience and mistakes are not tolerated'. This was my experience with the teacher, and I found it very wearing/ demoralising.
I just decided to be Pollyanna (not my natural default!). It's a job. I am there as it pays me, and for the kids - any friendships I pick up are a bonus. I smile, leave biscuits in the staffroom for halloween/ xmas etc...ask about holidays and weekends, and most have thawed.
I think it's not really personal , it's just that schools are ridiculously busy, and take a lot of physical and emotional energy. Just smile a lot, ask about weekend plans, and then pick up a book/ check your phone/ read a magazine with your lunch. It's still early days.