January 13 update:
Read 3 pages of 時をかける少女. This time it was very action-filled, and I had to look up more words than in the past few days, so I feel exhausted, and at the same time still a bit vague on the exact events (perhaps I should’ve looked up even more words…)
I’m thinking that maybe I should check out the book club’s discussion. I actually found out about both 時をかける少女 and よつばと！ by virtue of seeing them in the master book club thread, and I definitely picked them up with the intention to at least lurk the club threads, even if years after they read them. But somehow I never did 
This is very reassuring! I felt it would likely be that way, because my prior experience with languages, both foreign and native, was somewhat similar. But after plateauing with Japanese for a while, I had some doubts whether what I had been doing was effective, so thanks for confirming that it worked out for you! Now I feel somewhat relieved 