I am in exactly the same situation, I have only told one person (who I knew was on antidepressants a few years ago) that I have started taking lexapro.

I really dont want to tell my parents as they are of an older generation and just dont understand the whole chemical imbalance theory....but if your parents are educated they should realise its a physiological imbalance, not a character flaw!

Let me know how it goes...