Talk to the company and explain the problem.
Perhaps they can agree to you working part time for a few months.
I'm a month away from completing my two year program in Computer Network Support Technician. I wanted to take my A+ Certification. I'm not ready yet but I will in the next two months. There is a job offer in computer network support that this company is offering me. I'm not sure if I will be able to work while studying for my certification test. At the same time, I do want to start in the IT industry right away. What should I do? Any suggestion?