Buying Alochal

I was inline buying food for my household, I have 2 children at the ages of 9, and 13. I went to Wal-mart with my 9 year old son and my 13 year old daughter. Along with the food I also wanted to get a 30 rack of beer for my Husband and I, to have a couple drinks later on that evening. Keep in mind I'm a fourty year old woman, and ofcoarse I'm of age. Well Wal-mart refused to sell me the beer! Do you want to know why? Well here is the thing, my 13 year old daughter, who is clearly 13.. Did not have an I.D. to show she was 21. Because I went into the store with my children and because they were 13 and 9, I was unable to buy beer for MYSELF. They said I couldn't because both children were underage and they didn't want Wal-mart to "serve minors." Although the beer was Clearly for me, I am a grown woman! I'm sorry that I went to get food for my Family, and brought my family along. And also wanted something for myself, is that so wrong? ... I thought that was crazy! What do you think?