Blonde at School

Day1:
A blonde comes home from school and says to her mum,"We learned how to count up to 5 today mummy. I got up to 10. Is it because I'm blonde, mummy?"
Mum replies: "yes dear"

Day 2:
"We learned how to do the alphabet today mummy. The others only got up to E and I got up to S. Is it because I'm blonde, mummy?"
Mum replies: "yes dear"

Day 3:
"We learned about breasts today mummy. All the other girls are flat chested and I'm a 36DD. Is it because I'm blonde, mummy?"
Mum replies: "No dear, it's because you are 25."