my gf mentioned my stutter for the 1st time.

my gf mentioned my stutter for the 1st time. I'm 22 and i've been dating my girlfriend for 2 years. she never mentioned or launched a conversation about my stuttering. so we were hanging out in that restaurant which you have to order on the cashier stand then take your food and sit down anywhere. i asked her what does she want and then while i'm going to give our order, she told me: don't hesitate!. i went like: what are you talking about?! she repeated: don't hesitate while you are giving the order, you look so worried!. but i wasn't worried or anything for real. i felt so embarrassed and to be honest i got hurt. why would she mention it in that way?! i feel like she said that in a bad way, i didn't like it all. also I'm the one who usually speak in public, so it was unusual for her to mention that and tell me to not stutter. is she rude or I'm just overreacting?