YA Sci-fi/Fantasy Alchemist???

Sorry for the awful summary, but I don't really remember much, just bits and pieces.

The cover of the book was a tan color with an alchemic circle.

The main character is a male in highschool. He forms a bond or a fascination with a girl that is generally considered a geek (I think?). He later goes to a traveling circus (or maybe it was a fair) in town and learns how to do alchemy—and towards the end he goes into the girls house and finds everything frozen. Her parents appear to be sleeping and haven’t aged in years. They later have to defeat the man who was teaching the male.

I am so sorry that's all I can dish out. Hopefully someone will be able to help.

Alchemy by Margaret Mahy? I read it a while ago and hardly remember a thing about it, but it seems to fit.

I'm pretty sure that's it, Thank you so much for your help.