Must I attend yoga cles in order to learn the advanced poses? I'm really shy / suffer from social anxiety..

I've been doing yoga on and off on my own for the past 4 years or so, just trying out poses from yoga books. I do complete sessions. However a lot of the advanced poses like the shoulderstand, headstand, i.e. inversion poses... I can't yet do. I don't have the required balance and strength to do them steadily, and I know I will hurt myself whenever I try. I do stuff like the plow, the candle, etc, mostly the beginners to intermediate stuff I can manage on my own, but I'm scared of doing complete inversions and I know I will just fall and hurt myself. Do you think I must attend cles in order to learn the advanced stuff? Perhaps I'm not even doing the beginners/intermediate stuff right and I don't even know it, LOL! But I am soo so shy. I've tried attending 8 antenatal yoga cles while I was pregnant, and even then I was so self-conscious I could not fully relax into the sessions. I don't know what to do. I love yoga, yet I can't relax in a cl!!