it reminds me of one of 2 Live Crew's old song that in one verse they go "I WONT TELL YOUR MOMMA IF YOU DONT TELL YOUR DAD"
Most Helpful Girl
Well as a mother it as strange that she wasn't concerned of her daughters attire
But yeah, she probably saw you as a little curious boy rather than a potential threat to her virginity (if at all)
Theres also moms that just like boys more than girls (like my grandma)
Even if you were a lazyass and her girl were a straight A student you still might get favored in that case
Plus your a "family friend"
Basically the son of her friend
Usually in that case its like they consider your like their own
And to addults they always find it cute when the children grow up and find new things about themselves and the environment
Other than that, I don't know XD