It takes them ten volumes to even CONSIDER telling the rest of the friend group about their relationship. So I doubt that'll happen anytime soon, which is an obstacle to showing development. I'm big on pacing, development, and "show don't tell" storytelling in general, so this manga is kinda lagging in those aspects. But then again, it's about showing off an innocent couple, I guess; there's not a ton of drama from third parties and they get along exceedingly well for two people who are basically new to relationships, disregarding the lesbian aspect.