Sponsors should be individuals that are active in their catholic faith and inspire confirmation students (confirmandi) to live as a fully practicing member of the Church. These individuals should be actively involved in their confirmandi's sacramental preparation.
What makes someone "active" in their Catholic faith?
Try to find someone local, if this is not possible it's okay.
Although high school aged sponsors are allowed, they should exhibit a spiritual maturity that merits the spiritual responsibilities of what a sponsor is supposed to live out.