I got cash for silver

Last week I saw a beautiful dress in the local boutique. It was so beautiful that I knew that I wanted to buy it. There was only one problem. The dress was so expensive that all my saving were not enough to buy it. Of course there was always an option to ask parents for some money but I knew that it would not be so easy as my father did not like when I was buying to much clothes. He also knew that I had this bad habit of buying but not wearing clothes that I bought. Anyway without no other choice I went to ask my parents for money. My mother said that she could buy me this dress but then my father quickly said that he will not give me any money for another useless dress. I was so angry and I wanted to prove them that I did not need their help that I did something stupid. I had this old silver jewelry from my grandma and I decided to sell it in order to get cash for silver. I got even more cash for silver that I thought and I bought the dress. Then I saw my mother my new dress and she asked me how did I manage it to buy it. I told her about the old jewelry and that I got cash for silver and she started to cry. I was shocked. She could not believe that I could be so stupid. The silver I sold was priceless to my family and I exchanged it for a stupid dress. I was grounded for three months but I realized that I did something very wrong. I do not know how to apologize my mother.