I kept looking for reviews that spelled out certain information, so this is for anyone wanting the following:
1) Episodes 1-18 take place in high school (not much in the way of "butterflies" during these episodes)
2) Episodes 18-19 are transition episodes (I'd say most of the tummy butterflies happen here)
3) Episodes 20-onward take place after high school (some butterflies, but not a ton; just kinda cute.)

All the main characters are likeable. The secondary characters are also likeable.
There is a wee bit of angst, and it is super well done. It also gave their story a lot more depth. But this is a cute love story, not a melodramatic one.