I'm sorry you're struggling with so much anxiety. It's good your dad is doing well though. I can't really answer your question with regard to OCD. Based on my own personal experience, I would say one is never too old to have OCD develop or worsen. But that's just my opinion. Perhaps other members, here on PC, will have some thoughts they can share. Talking about it with the mental health professionals in your life is probably the way to go.