The shifters are SRAM X7, so she's off to a good start I think. I read somewhere thst the only difference between X7 grip shifters and the more expensive models is in the casing+rubber design, the mechanism is the same.

Also, this park I mentioned has a flat section with wide pavements too, before you go deeper into the park where there's very mild singletrack. I think it will be a good platform for getting the hang of everything if we just avoid the weekends - it's crowded then, and the little kids are everywhere on the paths. I'd rather not place anyone in danger!