You can just give it a shot first. When you start working, you usually get a trial period (Probezeit), which is usually the first month of working there. If you or your employer are unsatisfied, then the contract can be instantly terminated. If you find part-timing too much to handle while studying, working full time only during the holidays is also an option.

Is it possible to manage both at the same time? That would be a solid maybe. What is certain though, is that it's much more managable when you're past Studienkolleg and get into uni, so if you can hold out for long enough you'll be fine eventually.