Newbie LJ question

Here's a question for you lj gurus out there.

I recently noticed that content was being blocked from me and replaced with the 'not appropriate for minors' message. Forcing me to click through and agree and /still/ have to click through, on each individual message.

So my questions are..

1. Is this new? Or something old I just didn't encounter before? Maybe not entirely new, but a new tweak?

2. Is there a way for me to change my settings so it always assumes I'm... 14 was it? Random age.

3. Is this a user setting? Like you decide you have adult content, so you'd better mark it as such? Or does lj automatically do it, as I assume it does. And does it go by post or do they suddenly paint the entire lj as adult based on one post?

I wouldn't want to say the word 'breastfeeding' accidentally and suddenly have no readers.

Thanks in advance.