Yeah, it's a good thing to be considerate. It's also a really good thing to not tend or caretake another person's emotional reactions to the truth. EP, it really sounds to me like you did *precisely nothing* wrong. L is really laying a heavy trip on you about shit she definitely needs to take a look at. The real red flag is always this "I don't even know you! You aren't the person I thought you were!" This is some toxic shit and goes to a shaming, manipulative and accusatory place against which there is no argument. I always want to say "wha wha what? I be me, right here, like always!" My mother used to say "I love the good Peter, *not* the bad Peter." OMFG! Is it any wonder I got some issues? haha.
So keep soldiering on and take heart that you were able to be honest. If L can'rt get next to your authentic enthusiasm, that's her problem. End of story. Save feeling like a screw up for when you really do something wrong.