Should kids be spanked at 13?

I'm 13 and I think I'm to old to be smacked Until yesterday I hadn't been smacked since I was about 10 ...but after threatening for the last few weeks (I've been at war with her) to give me a 'good hiding' if I carry on backchatting etc... (I didnt beleive her) but my mum finally went through with it and yesterday she caught me and my younger sister in a lie about school stuff. After we were both sent to our rooms I could hear her smacking my little sister which I thought was funny at the time but next minute she walked into my room holding one of my Dad's size 10 shoes and before I new what was happening I was bending forward whilst she whacked my bum a few times really hard with the flat sole of the shoe!! Then I wasn't laughing It was soo painful and shocking that I was yelling everytime I felt the shoe whack my bum .. I think I got about 7 or 8 whacks and ended up with a really sore bum!! I was really shocked and thought she'd just been coming to ground me or stop my allowance or something but she whacked my bum really hard instead!!! After I'd calmed down, I started thinking ...i'm too old for this!! and since then I've been trying to tell her I'm to old to be smacked especially since the last time was years ago - how can I persuade her I'm right I dont want my bum whacked with that horrible shoe again!!