I had just finished teaching a drop-in beginner class to a group of 14 students. The music for the milonga was playing, and one couple from the class started to change their shoes. I encouraged them to stay a bit and dance. One of them replied "We want to get good first".
This reflects a major fallacy among a lot of tango students - that they can learn to dance in a class.
You cannot learn to dance in a class. Classes give you tools for dancing - tools that you can then use to learn to actually dance. But classes do not teach you to dance. Neither, in spite of what many dance teachers tell you, do private lessons.
You learn to dance by getting out on the dance floor and putting to use all those tools and concepts you have been learning in classes and private lessons. Until you do that, you have not begun to learn to dance.
This is even more true for Tango than for most partner dances, given the improvisational nature of the dance. Almost anyone can learn choreography in a class. But improvisation can only be learned on the dance floor.
Beginners who start dancing socially from day one become good dancers much more quickly than those who wait. Don't be afraid of developing bad habits. Bad habits can be corrected. And don't be afraid of what other people think. The ones who matter will respect your determination to learn.
So get out on the floor and dance - it really is the only way to learn.
A brief note to experienced members of a tango community. Encourage your beginners! A tango community that does not grow eventually dies.