Is it normal to get turned on by my mom seducing my uncles?

Hi friends,

I am a 25 years old Indian guy and since I was a child, I've always seen my mom going over frank with everyone, be it my uncles or my friends. She is quite sexy even in her late forties with a fair complexion and 38D firm and voluptuous boobs. No doubts, she would have been a bombshell during her younger days. She never hesitates to change her clothes even when my uncles (father's brothers)are around.
From the very childhood,I've never seen her asking my uncles to go out of the room when she changes. I've seen her stripping to her bra comfortably in front of them even facing them, thereby, giving them full view of her full curves. I always wondered seeing her this way as nobody else in the family used to be this bold.
I've always doubted if she is in sexual relations with them. Mom always greets them with tight hugs. I've even seen my uncles inserting their hands inside her blouse and she reacts casually.Once on a beach, she went topless quite comfortably in front of me, my dad and around 20 other men. I get really turned on by all these acts of hers and have even masturbated several times thinking of all this.
Is it normal on her part? Does she just show her affection by all this or there is really something slutty about her? And is it normal for me to get turned on by seeing all this??

Kindly give genuine replies.