質問者様の英文を訳す前に、見せびらかすことは「show off」と言います。
「I want to show off my signed baseball」
さて、長分の方ですが ：
"I don't know anything about baseball but I would like to see MLB in the flesh, which I've only ever seen on TV before. Also, I want to get a signed baseball, take it back to Japan and show it off. Though I don't have a favorite player in particular."
イギリス 
