Much younger lesbian BFF & roommate, big problem

My hubby & I recently moved into a house (purchased by BFF parents) with my much younger best friend. I am in my mid thirties and friend is early 20's. It's a nice house with alot of space and we pay very cheap rent. BFF mom is here all the time and does nice things like bake banana bread and wash dishes. The mom stays regularly due to long commute home when she works in town & enjoys working on projects around the house and spending time with her daughter. She is a high energy woman & is kind and sweet. I'm actually closer to her moms age than my BFF. the mom and I have formed our own relationship/friendship. I would say that although I love and care about the BFF, it has become obvious that she is a kid in a lot of respects. I would say that my friendship with the BFF is one that is sort of like a big sister/little sister one. At times I don't even notice the age difference and she glows with maturity, others, not so much. BFF is gay, and her GF has moved in....which is ok. I wasn't asked, but GF is a nice person and I don't have any complaints with regards to her. There's a bunch of little stories that I could include to paint a bigger picture but I will get to the problem FINALLY, lol. BFF told me I was disrespectful to her mom. She told me that it's "not what I say, but rather how I say it". I asked for examples, got a couple. The examples had validity in the sense that the specific things said or "not said" were times that mom & I get a little snappy with each other. But disrespectful? No, absolutely not. Anyway- 2 weeks have past & we have tried talking, twice, and can't fix, she is acting so weird & I get so heated I restrain from talking at all to avoid yelling or sayi g something in anger. I've cleared the air with the mom (SHE said that she didn't have a problem!), talked the situation with different people in my life and nobody gets why this has turned into such a big deal. With live with each other and usually talk by text everyday, and thi gs are tense & awkward. I don't know what to do. Please, if someone got all the way through this, could you please give your 2 cents? I'm sad, angry, annoyed and confused. I love this girl but do not have much more patience for this. Pretty soon I'm gonna say all the thi gs I've beeen holding back and speak to her like an adult talking to a teenager- she is acting like a child and I'm over it. Please reply!!!!!

You need to shatter the awkward tensity with a giant hammer of blunt, adult conversation. Just approach her or better yet, set up a time to talk alone about the issue. I know it's hard dealing with young people (I am one), but speaking down will only cause the situation to turn even worse. Just come straight out and ask why she is acting this way. Tell her you made amends (although hardly any were needed) with her mother. Just be completely truthful and down to earth with her. Try and show her you are legitimately trying to make the situation better and see if there is something other than the mom incident that is causing her moodiness. I wish you the best of luck!!