I would like to know if I can do the A-levels in January 2019, because I will not be able to do them in June 2019. I am going to do four or five A-levels, so for me it would be terrible to wait until June 2020
I would speak to whoever deals with exams in your school/college and see if they can work something out for you, it really depends on your personal circumstances so there's not much general advice I can give you, sorry
Moved to the A-levels forum, though I think the advice you've had so far is solid.
Bear in mind we're talking about dates that are a little way off, your personal circumstances may well change (I don't know what they are, so I can't speculate beyond that). Try to be too panicky or concerned right now.
And please don't do 5 A Levels, can strongly advise against that from some relatable experience.
I would not study for one A-level, because it is the Italian A-level, and Italia is my first language, so I don't need to study. I would only prepare four exams