Well, you should. Her epic history videos cover all the major houses (Baratheon, Stark, Targaryen, and Lannister). She has other videos too.
If you haven't read the books like me, her videos helps me appreciate the TV show immensely. I previously blogged about my Top 5 YouTube Channels for Comic Geeks, and she's listed there as being one of my favorites. I really enjoy these content creators' channels.
If you just want to hit play once, here's Comic Book Girl 19's Game of Thrones videos playlist: Game of Thrones Videos & GOT Epic Histories Playlist. It will play in the order one after another.
Keep in mind the videos are made over a few years. But if you want to just watch some histories of the different houses in Game of Thrones, I posted them individualy below.
Just a warning that she does cover stuff from the books, but I don't consider them super spoiler-y or anything.