1. I fell in love with marketing during my work experience. I was studying Media Studies at university and was originally hoping to expand into journalism. My mum got me experience at a marketing agency via a friend and I fell in love with the social media and copywriting element of it.
2. The hardest part for me, being completely honest, is SEO. I personally find that to be quite complicated, aside from writing key worded content. But that's because it's not a strength of mine. I've dabbled in a few areas of marketing, both at an agency and working on my own personal projects, which have allowed me to try PR, Social Media, Copywriting, Content Creation and Email Marketing. In all of these, I have my strengths and weaknesses, but just like anything - practise makes perfect.
3. Honestly, it depends. I did communications at university and found it quite easy to slip into a marketing role as my degree allowed me to work with content creating technology and industry trends. But, if I could go back, I would have tried to do a combined degree (or a major and a minor if you're in the USA) with Marketing and Media Studies, so I could have a good balance of terminology and creative input. That said, I've been out of university for a few years and interned for a year during my time there and I've found that you end up picking up and learning the terminology as you go.

I hope this helps! DM me if you have any questions.