Hello!
At the start of my flights, I find I'm still quite slow to get myself started...
That's totally normal and no problem at all. Most important thing: Allow yourself to take all the time you need and under no circumstances get yourself into a rush. The time "saved" by doing stuff in a hurried way will be spent ten times for rectifying the consequences of your mistakes afterwards.
As others already said: Organize your gear in a reasonable way (at home, not when already inside the aircraft!), make the best use of technology unless you want to practise "manual" flight planning in view of your coming ATPL course and rehearse (so to say) your flight mentally on the way to the airport: What needs to be done in what order, where might I encouter unusual situations and so on.
From your training you are used to a speedy way of doing things because (most) flying instructors don't like to waste unpaid time on the ground and will do a lot of your work for you, often without even telling you. Also, they will have organised the tasks in an optimised way, again without telling you. Now you are on your own and have to catch up on your instructors, which will take some practise....
Mind you, when I fly at work (commercial bizjet operation with two-crew) we are required to be at the airport at least one hour before the flight. And very often, we need every minute of that hour, even if many tasks (like flight planning, catering and aircraft cleaning) are done for us by the company. So never mind your "slowness"!
Happy landings
Max