Re: career enquiry
SEM is a broad field and Google Adwords is one of the advertising platform which many advertisers use to promote their business online and achieve high ROI. You can certainly have a bright career in this field but before that you need to have the basic level of understanding how Google Adwords works. Once you know it, then you should try to complete the Adwords Certification. This should help you in achieving your aim.
I would suggest you to start with this below Adwords PDF:
You can also read about the Certification Program here:
Hope that helps!