How to explain myself?

I'm a university student. My major is nursing.
But,this is not my first time to go studying at university.
After I graduated high school, I entered university and my major was economics. After I graduated university, I worked for 4 years.And now, I have entered Nursing university again.
When I try to explain my story in English, it is so difficult for me.
Please teach me a good way to explain of myself.

Note: It is a good notebook entry. You need to be careful with spacing after words, and past tense needs more work (entered) rather than "have entered"

You are doing better in your chosen study language than mine.

I hope that your studies are successful.