A "M" 11.3mm bore verses a "ML" 11.65mm is one of resistance. At your daughters age, in theory it would be a little easier to play as she won't have to generate as much air support for her notes. That said, if you haven't played one, I found this trumpet to be wide open, and it took a more energy to make it sound good (for me that is). I play on a Bach Stradivarius #180 with a #37 bell.
The Bobby Shew is a beautiful professional trumpet. It's considered a "lightweight" trumpet which I found made it a bit more responsive.
For general questions on purchasing a professional trumpet for your daughter that she can grow up with and use for the rest of her playing career, here's a site that goes through many questions, and looks at Bach, Yamaha, and Getzen professional trumpets:
https://trumpet.biz/trumpets/best-professional-trumpet/Good luck to your daughter and her trumpet playing!