i'm having a GW watch party with my friend too (its her first time with mecha anime) i'm hoping to get her to watch 00 as well but it might feel like whiplash going from tossing a cabbage to distract the enemy to NOT KILLING THE PERSON RESPONSIBLE FOR A CIVIL WAR JUST BECAUSE YOU HEARD CHILDREN SINGING
First of all, deciding to have a GW watch party is 10/10 the best thing anyone can do right now. I think everything I devote my time to should be something I loved years and years ago. What is your friend thinking of it? Who is her fave pilot so far?? I am finding that my tastes have changes a bit since my initial watches back in the day...
Secondly... I have never watched any other Gundam series!! Gundam was my gateway into fandom and from here I jumped into Newsies and LoTR RPS and HP and so on over the last *cough* 20 years... Should I watch 00? I have heard it compared to GW but have still never ventured out... though, your description of killing over children singing is intriguing...