My [19/M] recent girlfriend [19/M] told another guy she misses him

Let me get you some background on my girlfriend. Shes known by people to be extremely sociable, and very affectionate towards everyone. Shes the nicest person I know and innocent as well. Also is a very touchy person.

So I got this girl to be my girlfriend last night. I couldnt be happier, we exchanged many "i love yous" all night, sat on a park bench together and cuddled for hours. However, as we parted each other, about half an hour later my close friend, and also her very close friend, texts me showing some msgs hes revceived from her at that time. Shes sending him msgs such as "i miss you so much", "i thought you cared about me" etc. and after asking about it casually without showimg my jealousy, according to her she was feeling a bit tipsy when sending those msgs... even though she was fine while with me before sending those msgs. Some important other information is that this guy friend of mine lives far away and hasnt visited where us two live in about two months as he studies interstate. . Keeping this in mind should I brush this off because im overreacting like most overprotective people (im known for this among my friends) or should I confront her and say that i feel uncomfortable with her telling her guy friend that she misses him alot? This is the first gf Ive had and Im really not sure what to do. TL;DR my recent girlfriend texted her guy friend that she misses him alot