Tale
Story, Legend
A language about things. This is a confusing one. Just think of it more like someone talking about things, anything, really. Someone who just talks about things is someone who tells stories. So, this word means tale or story or legend (not the Tom Cruise one, though).
ものがたり
The reading for this is messed up. You have 物 as もの, which is fine, but 語 decides to go all crazy on you. Maybe you've heard the word ものがたり before (it's in some film names / book names). If not, think of a story being told about a great gatling (がたり) gun that wandered the land, mowing everything down in its path. It's a terrible legend, but what if it were true???
物語の主人公にでもなったつもりでいるんだろう。
I think she's acting like she's the main character of a story.
竹とり物語は日本の有名な物語です。
The Tale of the Bamboo Cutter is a famous Japanese legend.
今物語を書いているんです。悲しい子犬フェチの男の話です。
I’m writing a story right now. It’s about a sad guy who is obsessed with puppies.