Your toddler is 35 months old!
Toddler social skills are a work in progress. Your child just doesn’t understand what makes other people, and children, tick. You often may see her just watching other children play without joining in, or playing alongside other toddlers, doing the exact same activity but totally ignoring her counterpart. It’s called parallel play, but although your child may appear to be unaware of other children even though they’re sitting right next to her she likely is very much aware of them and keeping a close eye on what they’re doing! Even though she may not interact with them she is getting a sense of companionship that will gradually develop into co-operation and shared play.
Look at our Expert section for toddler advice on anything from tantrums, to imaginative play.