What is the color code of dressing for a meeting of a red hat society club.?

Red Hat and Purple Attire (for those women over 50) and Pink Hat and Lavender Attire (for those women under 50).  That's the only criteria and color code.  On their birthdays, the ladies swap the colors and put the reverse on their head and bodies.  For example:  If I am a Red Hatter celebrating my birthday month, I will wear Purple on my head and Red on my body.  Fun, huh? 

When I am Old by Jenny Joseph

When I am an old woman I shall wear purple
With a red hat that doesn't go, and doesn't suit me, ...

http://www.barbados.org/poetry/wheniam.htm

There is a poem that explains it, "When I'm an old woman, I shall wear a purple dress with a red hat."   Find the poem and you will understand the reason for the group.  Also, you must be of a certain age to wear purple and red, maybe 50?   Younger women must wear lavender and pink until they become of age.  It's a fun group, because it is just for fun and nothing serious.

I had read the poem when I was too young to join.  I loved the poem and the attitude of the narrator of the poem.  I didn't think any more about it until I saw a wagon load of Red Hat Ladies in a July 4th parade.  By this time, I was old enough, and the idea appealed to me even more.  I thought I would think about it.  That day, I was in a Hallmark store and two of the Red Hats came in.  I asked them what the rules of the group were.  "No rules...just fun..." was what they said.  I joined the next day.  The groups differ, and you might have to try out one or two before you settle in, that's what I did.  In this day and age, to belong to a group without any rules and who's main objective is to have fun...well...what's wrong with that?  Eh?