Gender stereotypes. The typical "female" is often portrayed as shopping addicted, always on her phone, and someone who hates physical exercise of any kind. Sometimes it may be hard to step out of the stereotypes and be oneself due to the fear that someone may criticize them for playing sports, which sadly many people think is a "guy thing".
Peer pressure from other females can contribute to this as well. If a girl even expresses her interest for a particular sport, others may call it "lame" or "for the guys".
It's kind of sad in a way, thinking we have come such a long way yet women are unable to pursue their dreams without persecution or hate.