On the contrary, you should definitely stare in ALL the red windows.
When we went to Amsterdam just recently, we definitely partook in the red light district, and it was awsome.
The min. age for bud is 18, not 21.
Shrooms are cool , I hit up the Magic Mushroom, but you should definitely set aside a whole day if you are going to do that.
We caught a little bit of anti-American attitude in the shops. Expecially the real local ones like Katsu and Rusland.
It also seemed like people were prejudice towards us 'cuse we were smoking out of bowls and not rolling spliffs, except in Grey Area.

Either way, go, words can't describe it , Amsterdam is awsome.