My brother embaressed me in front of his friend ?

My 17 year old brother embarrasmuch tonight so I hwas downstairs and hiand his friend came home from a party I was in the kitchen before they were I was eating they were both at the table eating so then I went to the fridge and started eating cookie dough his friend was making a joke about how my brother likes younger girls. He goes out with a 14 year old when he is 17 I went to say that to his friend that his girlfriend was my moms 8 th grade student last year my brother didn't even let me finish he wacked me and told me to leave him alone and to stop trying to make fun of him. I was just stating a fact in all seriousness I was so embossed this isn't the only time he doesn't pretty much every time his friends over he says for me to go away when I was there first. Ugh it's annoying and embarrassing.