It’s never too late! I have a friend who only read them for the first time last year, and she’s an adult in her mid-30s.
Girl, I’mma have to bring you a book.
I will say that Harry grows up with the series, much as the kids do in the movies. So things get more complex and darker as the series moves on, and the first book is really laying groundwork for the amazingness that follows. I read the first book at 13, so I related to 11-year old Harry in a different way than I think adult readers would. That said, I have plenty of adult friends who liked book one as adults, for what it’s worth. But most of them agree it gets way better as it moves on. Personally, I think book 6 is her best work, but book 3 is where the series really takes off (in my view). I don’t want to spoil anything. Just take that journey with Harry. It’s so worth it.
In the end, what I can tell you is that when the going gets tough, the tough re-read Harry Potter.
: )