AITA for telling my girlfriend to shut up and let me talk to the cashier?

My (17M) went to get some groceries with my girlfriend (18F). She was looking at some phone or something so I just went and got everything we needed while she stayed by the cart. I went to this self-serve cart thingy. I picked up some chocolate covered pretzels and was about to scan them when it said I needed the cashier to scan them. <br><br>So I just put it all on the belt, and go to another self-serve cart. I pick up about 10 of those s’mores bars and some other snacks. I get to the cash register and the line is pretty long. So I put all the self-serve stuff on the belt and I carry the s’mores and pretzels to the other side to weigh them. I weigh them and I put them in a plastic bag and carry them on top of the other groceries. The line is still pretty long so I stand over there for 10 minutes just checking my phone. I jump in the quick line with 10 items or less, sort through my stuff, and pick out 4 of the s’mores bars. I put them in my bag, and pick up 2 more of the s’mores bars, and put those on the belt. I sort through my stuff again and pick out 5 more of the s’mores bars, and put them in my bag. I put 2 more of the s’mores bars on the belt. I sort through my stuff again and pick out 4 more of the s’mores bars, and put them in my bag. I put the last 2 of the s’mores bars on the belt. Then I jump back into the long line with all my stuff. After 25 minutes I finally get done, and my girlfriend is staring at me weird. <br><br>We get home, and she’s staring at me a lot. Me: What? She: How much do you eat? (kinda joking) I: Not your business, I paid. She: It’s still a lot of stuff. Me: It was 20 bucks. I didn’t spend that much time for that much money to not get as much as I could. <br><br>She’s still looking at me weird. I go about putting the groceries away, and she’s silent. I’m doing my thing, and my mom shows up unannounced. My gf is still silent. My mom: Hi! (to my gf) Oh hey dude, what’s up? (to me) <br><br>My gf: He ate so much food. (She’s never been the quiet type, but she’s never been my mom’s favorite either.)<br><br>My mom: Is he okay? Is he hungry? (to me) You good, son? <br><br>My gf: No, I was just wondering how much he eats in a day. <br><br>My mom: Well the answer is A LOT. (laughs) We don’t need to know that sweetie. (to me) Don’t you listen to your father? (to my dad) See? He doesn’t listen. (to me) I mean, I get it. You’re growing. You need a lot of food. <br><br>My gf: No, I just want to know. <br><br>My mom: Fine. He eats a pack and a half of gum a day. He eats 2 or 3 sandwiches for every meal. And he eats all the snacks in the house. <br><br>My gf: (she’s laughing now) Okay, thanks. <br><br>My mom: (laughing) No problem, sweetie. (to me and my dad) Don’t you just love how your bodies crave nutrients? (to my gf) Now stop worrying about him and help me with these groceries. <br><br>My gf: Okay. (picks up some of the bags and helps my mom)<br><br>My mom: (to me and my dad) I swear, I don’t know what they teach kids about food these days. (to my gf) Oh don’t look at me like that! I know you eat your fruit! (laughs)<br><br>After that, my mom and her helped put away the groceries, and my gf and I played some games and did some stuff. She didn’t really bring up the food thing again, but she did give me some Lifesavers.