A great way to prepare for your first camping trip is to go camping in your backyard.
You don't have to worry about forgetting anything.
You don't have to deal with gross camp bathrooms.
You can practice setting up your tent. (As opposed to having to do it after an exhausting car ride).
It helps you to realize what you need on your packing list for camping in the future.
If you have kids, it gets them familiar with the tent, a sleeping bag, etc.