Re: Starting in Sax Playing focused in Jazz
If you can learn on the metal mouthpieces, I suppose that would be OK. But most people start on a hard rubber mouthpiece, usually one with a fairly closed tip like a Selmer C*. The less air you have to push to get a good solid tone, the more you can concentrate on fingerings and etc.
I was taught to always warm up with whole notes bottom to top chromatically. Concentrate on intonation and consistency. You should definitely get your feet under you technically before you worry about jazz. Most students of the past used the Rubank books - from elementary to advanced. Full of exercises that force you into good habits and proper knowledge.
Take it from someone who drifted into jazz and rock too early and had to go back and re-learn what I should have taken care of in perhaps years 4-5. I had my own band and got to thinking I knew it all.
Good Luck - and remember, the need for Practice never ceases.