I am 42 and have a ton of bags. My husband doesn't love it, but he has his issues too. Your mother is being verbally abusive about the whole thing. If you are paying for the bags and not running up a credit card bill, then let her rant and rave.
I had a mother a lot like her, but in a different way. She was always worried I was going to gain weight. I remember her saying "if you keep eating that way (I was 18 and I ate because I was a teenager) you are going to weigh 300 lbs". Also, no man would want me if I was fat. Well, I still wear a 4 or a 6 at the highest and fit in size 28 jeans, shop in the Juniors department, etc. I am married, so obviously her comments were completely wrong.
I would say something like "Wow, if you keep making comments like that, I will crave more attention and probably buy more designer stuff!"
Signed,
Rebellious daughter