I'm so very surprised to find out about somebody who's having Cosmos bipinnatus as his/her favourite flower. I love this plant, too. As in your case, it reminds me of childhood, when we, the girls, used to make false coloured nails from its petals (I know, I know, a bad thing to distroy the delicate beauty of the nature, but we were 5-6-7-year-old kids trying to imitate the elegant women
). I am now a bit over 30-year-old and I love this flower. Nowadays I find it more rarely in the gardens. I just saw it recently on my way from work and I wanted to know its name. And I found it this morning on the internet. And an hour later I found it here on TE. And I also found a person who has it as her favourite .Kindest regards,
Nicoleta