Active engagement in social activities is important to maintain and promote healthy aging. In this study, we further investigate how older adults take the initiative role to support their health and well-being. To understand their active participation towards aging, we conducted an interview study with ten retirees who are "aging in place" (adults 65 and older who live independently). Our findings suggest that older adults are naturally developing a network of connections, which we refer to as their safety net. We have identified five social circles inside this safety net: predetermined, chosen, interest-based, location-based, and shared-identity circles. Each circle has a different impact on the support of older adults’ health and well-being. Based on these findings, we suggest taking the safety net into consideration when designing technologies to promote and maintain healthy aging.