I want to play violin for the rest of my life as a fulltime job!

Well you start by starting to play for as many hours a day as you can.

And as to where to take lessons, most cities have a music school, or music teachers, ask a local school music teacher if they know any, Craigs list has all sorts of teachers,
Talk to music stores, many of them offer lessons, others have list of people who do lessons

In addition to the fine answer above, it would help to know a location where you would like to be making a living doing it full-time and what kind of violin playing it is that you want to do in order to give you the best answers here. Many people would like to do it full-time. Unfortunately, for a violinist who might want to play in a major symphony, or part of a chamber group that plays all of the time, there is fierce competition for those positions.

Now, if you already do or were to play more in a fiddle style like for dances or maybe be the violinist in a group that plays more popular styled music in the nightclub scenes, there is not so much competition.

Usually, in major metropolitan areas like say, Chicago, New York, Minneapolis/St. Paul, Los Angeles, etc. It is possible for a single violinist to make a full-time living as part of a small group of some kind. In areas like that, you could also be playing full-time in the orchestra pit for musical theater productions.

What kind of music is it that you have already played and would like to play, and what is a location where you would like to do your playing, please?