Well..if you want to own an inn, that would be easy! However, becoming a Noble is going to be hard and likely a group-effort by influential players. There are a few ways to become a noble, legally, and anyone can attempt them, however even the lowest noble, the count/countess, will likely have the backing of many towns and villages, and have connections that would make it difficult to overthrow them. However! There is a chance that you can marry into nobility or run a village well enough to take over the current count's title if he/she decides to retire, stops playing...or is the victim of a justified rebellion.