Being critical's an excellent quality. In fact it's one of the few things a guy must have before I can get really interested in him! You weren't displaying a critical mind, you were showing a narrow one, and that's why people reacted so strongly. I'm glad you see the point now. Any relationship between consenting adults is fine, no matter the age difference.
Just keep remembering that a critical mind does not mean you close off to everything not your own opinion. The best feature of independent thinking is to be open-minded and allow your own opinions to be challenged, too.
(the bisexual thing...... whole nother topic)