Hi there.
I'm Japanese.
I'd like to learn English.
I just started to use this website.
So I don't know what kind of sentence should I [I should] write here.
But if you are interested in Japan, let's be friends!
I can help you with your Japanese.
Regardless of <age or sex or nationality.> [In lists, add a comma between all of the items, like this: "Regardless of age, sex, or nationality."]
By the way, I'm sorry about my poor English.