I will ignore some comments here, because serious......
to the op, you asked the girl out she is bringing someone, you can tell her, oh I didn't know you are not old enough to go alone to other places, lets call this out till you are mature enough to do so.
I'm betting you are new and young, so don't bother to try to apease her in any way, she is used to it already, you need to stand your ground and not to be taken as a fool.
and even IF you accept, such disrespectifull thing and let the 3rd wheel join up, it become a gorunp setting, in group settings each pay his, don't you ****ing dare to be a chump and pay for her even less her friend
to the op, you asked the girl out she is bringing someone, you can tell her, oh I didn't know you are not old enough to go alone to other places, lets call this out till you are mature enough to do so.
I'm betting you are new and young, so don't bother to try to apease her in any way, she is used to it already, you need to stand your ground and not to be taken as a fool.
and even IF you accept, such disrespectifull thing and let the 3rd wheel join up, it become a gorunp setting, in group settings each pay his, don't you ****ing dare to be a chump and pay for her even less her friend