When looking for a new mouthpiece I think it is a great idea to try out a few mouthpieces before you decide on making the purchase. I have some recommendations for jazz mouthpieces that will help the development of a quality jazz sound. I believe that starting out on a hard rubber jazz mouthpiece will help develop a strong sound and feel for the jazz mouthpieces.
If you are just getting started in jazz band I would recommend trying out some Meyer and Otto Link mouthpieces preferably the hard rubber. These mouthpieces are not only great for beginners, but more advanced players as well. If you are a little bit more advanced with jazz music. I would highly recommend trying out the Vandoren V16 M/S+, Daddario Jazz Select (pictured), or Jody Jazz Hr*. These mouthpieces are high quality and reasonably priced!
Please reach out to me if you have any questions!