S.D.
First as the therapist if they think too much sleep is the issue. I'm guessing it's not. My first son took 2 long naps each day until 18 months and slept from 7:30-8 or 9 every night. He slept A LOT!!! But it didn't affect anything. My second son gave up the second nap around 11 months. They are just all different. I'd say go with whatever works best for the family. My kids had totally opposite nap schedules, so I was happy to see my younger give up his second nap so early, but I wouldn't have pushed it if it didn't seem to work for him. It sounds like she could give up one nap if you wanted her to.