Your drivetrain should be familiar to any bike shop mechanic and they should be able to adjust it or identify any problem. In the US, it is normal for a bike sold at a bike shop to include a free "tune up" return shop visit after about 250km (155 miles) to adjust anything that has loosened during the initial use period.
If it turns out that you ...
Even cheap components should shift okay-ish, unless they are badly worn.
Shifting problems are usually caused by any combination of:
Bad adjustment: Incorrectly set cable tension or limit screws.
Excessive cable friction: Due to bad routing, worn cables, worn cables housing, missing/bad cable housing end caps or very low-quality cables.
Bent derailleur ...