1. Basic courses for your BBA degree (like general education, maths., English, Economics, etc.)
If you are lucky, you should be able to start financial accounting after first semester.
2. No. The maths for accounting is very simple. What complicated is how they are calculated (the formula).
3. You should not do anything. Accounting is a step by step process. Accelerating will not do you any good. For example, taxation is a branch of accounting (which a lot of people know about). However, taxation does not always use the same method as your typical accounting.
4. Seriously - usage is the key. Watching movies and reading books help, but very limited.