Autism can appear in different ways in different children. My 2 boys are both on the spectrum but in some ways they are the exact opposite of each other.
IME behaviour can vary according to the place/situation. Ds1, for example, really liked his portage worker who came regularly to the house to do home visits. When he saw her one day at pre-school he barely acknowledged her presence. Ih his eyes she only existed while in his house, IYSWIM.
Ds1 used to be oblivious to me arriving to collect him from pre-school sometimes. It was hard to get his attention. At other times he would cry because he didn't want to leave. Ds2 has problems with transition and so gets upset when it's time to leave.
Sometimes my 2 boys can seem exactly the same as any other child. At other times it is obvious that they are somehow different.
Are you able to give a very general description of what concerns you?