There was a lot to enjoy about this book, with a fun plot and some decent characters (especially Merlin - and this is the first story I've seen to examine how aging backwards would really affect someone). 

Unfortunately though the writing let it down. One particular issue is that every character sounded like they grew up in the 2010s, with slang you would expect to hear from a teenager in 2021. Not only did that feel out of place for a book set a long way in the future, it's also going to date the book very quickly. 

I enjoyed the book, I'm just not sure I'm hooked enough to continue the series.