Hello, sorry I haven't been on in a while, I went on a little vacation and somethin' awesome happened
I met 4 Japanese girls my age and they were super nice. Between my broken Japanese and their broken English we had a conversation! I know I got nervous and probably was difficult to understand but they looked really happy to be talking with me and we exchanged email addresses. Anyway, we talked for about half an hour or so and they didn't use polite speech (I mean they didn't use ～ます forms) the entire time we talked. I used polite speech at first then accidentally started using plain speech since they were. Though I was paranoid of sounding rude... Is it fine for us to talk that way because we're the same age?
I also asked them if they needed to leave when we first started talking. I said 「今、忙しいですか？行かなきゃか？」 then I apologized for using 「行かなきゃ」 since I couldn't remember the polite way at the time since I was nervous. So was using 「行かなきゃ」 in this case inappropriate/rude? And I'm gonna send them an email tomorrow, so should I write in casual speech or polite speech? Is it bad to use polite speech when others (esp. people of the same age) are using causal speech? Like, does it sound stiff and unfriendly?
Sorry for all the questions! I'm still thinkin' about it a lot