I just finished reading Here’s To Us which was the follow up to What If It’s Us. I will say I was surprised in that it actually wrapped up the story, they could have drawn this out over several books, but probably best they didn’t. Again, I thought it was real well done, at first I thought it all wrapped up and fell into place too quickly, but after I thought about it, there really was no other way to do it, it makes sense.
I feel like I can eventually see a TV series, maybe movie, being made about this set of books, but I think it would have to be cast correctly. Also, they will need to use actors who are older than the characters (like they do in most shows) so that they do not age too quickly on screen. My guess is they could draw out the story (in a good way) a lot longer through a tv show and fill in some of the time gaps.
I don’t really have much more to say, what I said in the other post hold true here as well. I would recommend both of these books as a quick good ready.