Ditto what Kate said.
We also had a 'grazer' with Denna. I'd put the measured breakfast down, and by lunch she'd have eaten most of it, so I'd add another cup... repeat at dinner. I think she was only eating 2-2.5 cups at that age (also started on Diamond, moved to Solid Gold Wolf Pup, but I know there are better kibbles out there, now). Our vet also recommended the "pickup after 20 minutes" routine... but we didn't do that, either. I prefer to keep food low-key, to avoid resource guarding issues later in life - although at this age, that shouldn't be an issue - especially when you only pick it up because they're not interested in it.
Eating less and slower is much better than the opposite! Give her some time to adjust to her new home and routine, don't worry about it, and she'll grow as she needs to.
It will be way too soon when she's too big to carry around, so enjoy it while you can!