I went through this several years ago. My friends who are new to tango ask me about this. I hear beginners use it as an excuse all the time.
What am I talking about? Beginners who just sit and not dance. I agree that getting on the dance floor as a beginner is an intimidating experience. However, one needs to dance to get better. This is experience best learned progressively on the milonga floor, and not taking lessons forever.
The most common reason I hear why beginners don't venture forth?
"I'm a beginner... People will notice me!"
I've used it myself when I first started. My reason at the time was that, I did not want to be humiliated and embarrassed when people found out that I could only do walks. My advice is to get over it.
Yes, people will notice you—for the first 10 seconds! You, as a beginner, will become invisible quickly as it will be plainly obvious that you just started. People won't care unless you run into somebody, block traffic, kick or step on someone. So, keep it simple, be humble, and stay in the middle.
People watch good dancers intently. Not beginners.