I'm scared of old people?

Irrational fear of death. Most people have developed traits that bubble up because they fear death (even dating only really young women sometimes). Try to find a way to come to terms with your eventual mortality. Read Thanatopsis, by William Cullen Bryant. Try seriously writing your own obituary, your will. Make a list of things you want to do before you die, and start doing at least one, and putting a time frame to do others. Chances are when you have had time to process your discomfort with your own eventual death, you will loose your fear.