Why not a 6.5x47L, 6.5CM, .260 Rem, etc.? Start with some lower charge weight 100-120gr loads, work up to 130-140s and full power when she gets older.
Or a 6x47L, 6CM, 6XC, etc.? 105s @ 2600 to start, bump them up to 3000+ later on.
My daughter, who is now 17, has been shooting her 6.5SLR since she was 11. And my AR & .260 Rem with reduced loads since she was 8. Even shot her first bull elk @ 11 with my .300RUM w. Brake. She has taken 2 elk (1 bull, 1 cow), 2 mule deer bucks, a buck antelope, a javalina, and numerous varmints. Hope to put another big mule deer buck on the ground in 2 weeks. She is a stone cold killer. And a very good long range shooter with her 6.5SLR. She just smacked a squirrel at 741 yards on a cold bore shot on Saturday while tuning up for her deer hunt. Got it on video too.