An accountant should definitely be comfortable with numbers and working under pressure.
YouTube is of course a free+viable option as well: https://www.youtube.com/results?search_query=what+do+i+need+to+know+to+be+an+accountant
TL;DR: math, SQL/excel.
I hope this is helpful!
Number crunching, understanding of financial terms and metric is a given for an accountant.
I think where one differentiates themselves is actually deriving the insights from the numbers. This is where you provide your interpretation of what you think of the numbers, financial metric, ratios and what story they are telling.
This comes with experience. But you have to make a start.
Just remember - crunching the numbers - others can do as well (those who are trained)... There are few who can interpret and tell the story.
Hope this helps.
All the best.
From my own experience...as long as you like to work with numbers you should be fine :)
Hope this helps,