Not everybody has the same degree of flexibility. I'm not super stretchy and I'll never be. You certainly don't need to be stuck in "basic" forever. I am still able to do "advanced" videos just fine. If/when you're knowledgeable enough, you can modify the poses to fit your body.

You could try the same program again or perhaps even move onto another beginners program so you are not bored. I have also attached 3 videos for you to consider. Start slowly and don't overdo it. Hope you enjoy the videos.