Commoner

This is a major challenge, so choose carefully. The standard for all characters is to be of gentry blood, that is to say to be of the peerage or related to them. To be a mere commoner, with money perhaps and hoping to gain a title, is to be the lowest of the low. People will try and avoid contact and may refuse to attend your events. Gaining a title will be hard, and it is unlikely you will gain more than a knighthood or Baronet, maybe if you are able to pay through the nose a Baron with its access to the House of Lords.

As a commoner you will be expected to display a certain lack of knowledge of how the nobility behaves. You are the outsider looking in. You may in time gain public office. You might even buy a lower title. You will however still display your lack of class through your lack of education in social affairs.

Note that as a commoner it doesn't matter if you are illegitimate (it doesn't affect your prospects to inherit a title for instance), so that it negates that challenge.