It wasn't that long ago that I was in your shoes. I discovered that I got very little info that I could put to actual use in the selection of a mouthpiece. Nothing beats getting mouthpieces and trying them.
About the only useful bit of info all my experimenting produced is: Fat rims are usually easier for beginners. That's it. It all comes down to that. ( Let's see if that doesn't spark a comment or two.
) So the most common mouthpiece one sees in the public schools is a 24AW.Two generalizations that are of some use (to me, but not greatly so): A deeper cup will probably give a darker tone (which you might or might not want). And a bigger throat will probably put more weight on the bottom end of the tone (which you might or might not want).
Beyond that, I'd say start collecting and trying MPs. Use what works for you. I have all the standard Yamaha mouthpieces and am acquiring the replica series; all the Kelly MPs, the Conn MPs, some Bach, Faxx, other stuff. And my collection is pitiful compared to that of some folks.
Somewhere out there is the perfect mouthpiece. It exists. We all know it does. It's just a matter of finding it. After which, we can get back to searching for The Lost Chord and whirled peas.
