I found putting a name to anxiety helped a great deal. I spent most of my childhood not really sure why some situations filled me with crippling fear - and felt like a failure because of it. As an adult I've realised it's a form of anxiety - and also that anxiety definitely runs in my mother's family.

I think my teenage years would have been easier if my family had been willing to talk about our anxiety rather than just pretend it didn't exist.

There is of course a danger that the diagnosis becomes an excuse - which is a particular problem with something like social anxiety where (at least in my experience) the only path to improvement is to face your fear and do whatever you're anxious about.