Am I being overprotective?

My boyfriend and I have been together 3 and a half years. 
Anyway we were at some school tournament for sport and this girl from another state kept following him and then started messaging him. She was saying "I wish I could share a cabin with you. ;)" and "you're so cute! ;)" and trying to make him meet up with her one day etc. 
I hate this chic and so I asked my boyfriend to unfriend her on Facebook and stuff but he won't. Am I being overprotective.?