The computer aspect of mechatronics is not the same as the commonly taught computer aspects of office automation. It is much more hardware oriented. In an office system, if it takes an extra 500 milliseconds to paint a web page for you WHO CARES? But if it takes an extra 500 milliseconds to react to position feedback, that's a show stopper.
As Varadha points out, there are also concerns about feedback systems, motion control, the care and feeding of stepper and server motors, hydraulic systems, fluid statics and dynamics, structures, extensive mathematics classes and so many more subjects.
You have much study ahead of you. It will be difficult, but if you love this stuff, you'll really appreciate it.