In general, third-graders can be expected to have good social skills. They are able to meet and converse with someone new, whether the person is an adult or another child. They are able to answer the phone appropriately and to take a message, and they are able to keep up with their own belongings. Third-graders are able to organize their things and to get things back and forth between school and home, although some still need help with organizational skills.
Ask for a conference with the teachers who are talking about a life-skills program for your daughter to find out exactly what is involved. Since she attends resource classes, your daughter probably has an IEP (Individual Education Plan) and any life skills on which she will work should be spelled out in the plan. As you know, you will have input into your daughter's IEP and you should feel comfortable about the things on which she will work.