There's something about yellow

My daughter is obsessed with everything the color yellow, and has been for the last 6 months now.

During our music class the instructor dumps a pile of maracas on the floor for the children, of which only 2 are yellow. Every class M makes a beeline for those two yellow maracas. During the same class a pile of scarfs is on the floor - she picks up a yellow one every time.

In our other class when there are hoops on the floor, she goes for the yellow one. If she is given an orange duck instead of yellow, she trades another kid for a yellow one.

I opened a pack of crayons yesterday...out of the 50 she chose the yellow one.

When at Costco picking out flowers last month I had her pick some out - yellow roses.

We have a multi-colored pack of straws in the kitchen...she chooses a yellow one every time.

When I let her play with a canvas bin full of her shoes, which ones does she pick out? The green ones. Just kidding...the yellow ones of course!

Which color does she love to say? Yeh-yoh.

Which color ball can she pick out of the pool of balls? Yeh-yoh bahs.

What is her favorite fruit? Bananas.

I worry sometimes that this might be a sign of future problems with OCD, am I crazy? Anyone else's kids show a strong preference for a color?