I am usually pretty uncoordinated. What got me through learning to drive was saying the steps OUT LOUD. (That’s easier when you’re with friends or by yourself, though.) So, I’d be muttering to myself as I approached an intersection, “Foot off gas, press brake pedal, but not too hard. Don’t forget turn signal. Check for other drivers…” Eventually it became second nature. If an experienced driver can talk you through what they’re doing, that might help, too.
Practice practice practice - that’s the other key. Someone once told me that after 10,000 miles you pretty much have the hang of it. Things are certainly easier after 10,000 miles than they were before. Drive around an empty parking lot. Drive in residential neighborhoods (find one with lots of stop signs so you can get used to how long it takes for the car to stop). If you can find a visual cue to let you know that you’re in the middle of your lane, that helps, too. (In my dad’s huge Buick station wagon, if the hood ornament was lined up with the edge line of the road, I was good.) Consider parallel parking advanced driving, and don’t tackle it for a while. And make sure your mirrors are giving you just the right view. (I prefer to have mine set so I can see someone who is just off to the side of my back bumper. My grandparents preferred to be able to see who was next to them. Choose the view which helps YOU the most.) Oh, and if you’re short, make sure you can comfortably reach everything in the car and you can see well over the dashboard. Some cars are just not made for short people.
And take a deep breath. You’ll get through this.