It sounds like you are giving your daughters a "head start" in programming. It's like music. The best way to give a child an appreciation and interest in music, is to play an instrument and sing with them, when they are young. It somehow builds neural pathways automatically because they are so young.

I can just see 15 years from now, a post here on perlmonks,

"my dad started showing me Perl when I was little, and now I'm writing this module........".