Singleness is not a justification to worry. A distinctive of all followers of Jesus is that there is no place for worry in their lives.
It is only natural for singles to wonder who will take care of them in illness and old age. For some their greatest fear is to die alone and for others it is that they will be all alone in their later years.
The heavenly Father will care for his single children in old age just as he has throughout their entire lives. Our trust cannot be in a government, a 401K, a pension, church, family members, or friends. Social Security could go broke, the economy may crash, the church may close, and family and friends may die before us. Security can only be found by trusting in the keen attentiveness and care of a loving heavenly Father. (Matthew 6:32)
In reality there is little difference between facing the future being married or single. It is presumptuous for married people to think that their mate or their children will care for them in their old age because there is no guarantee that their mate or children will live past tomorrow. It is also assuming for singles to think that “if only” they had a mate and children that they would feel secure about growing older.
Worry is a waste of time and height of assumption. As Jesus pointed out “Can any one of you by worrying add a single hour to your life?” (Matthew 6:27)