Despite recommendations from others including some healthcare professionals, please note that research indicates that putting those with social skills deficits in social skills groups first can lead to an increase in problematic behavior. In addition, it leads to delays of their development of social skills as they do not have the skills 1:1 with a peer, so why would we expect them to have the skills in a group of 4, 6, or more peers.
Some things to look for as concerns can be that your child generally wants to interact with adults and/or much younger children. This is because adults are patient and do not discourage inappropriate social behavior as much as peers. They may play and interact with much younger children and their deficits in social skills place them at the same developmental age as those peers.