Is it possible to take an AP exam without taking the class at school?

Basically I am from Europe and I want to take AP Chemistry next May because I need it for University. I graduated from high school this year and kind of messed up the Czech exam in Chemistry so I’m taking a gap year now.

My question is - is it possible to prepare myself for AP Chemistry on my own at home? I did take chemistry classes at my school for 7 years so it’s nothing new, also I think that my English is sufficient.

What should I do? Buy some books? Do some online courses? What would be your advice?

I would suggest you take some AP prep book (like Princeton review, or Barron’s) and take a practice test to get a rough understanding of what all you will need to learn and already know. If you score 4 or 5 it will be simple. If you get a 1,2, or 3 it would suggested to take an online course. AP Chemistry is not something you want to self study the material for. It is easier with a teacher.