I would take classes, you need a solid foundation done correctly.
Until the dog’ growth plates are closed there are a few things that are minimized or limited to teach such as jumping and weave poles. Puppies can jump, and they can jump high, however in training agility you don’t want to ask your dog to jump repeatedly. Puppies deciding to jump on their own is fine because they will stop when they need. I teach beginner agility and for puppies we keep the bars very low so there really isn’t any jumping involved. We do start puppies jump training with good technique and they learn to go through the jump posts and you can even start training some handling without repetitive jumping. We don’t want puppies twisting their bodies- fine if they do it in play, but not in repetitive training. I teach the 2x2 method which allows us to get the basics trained. You can work on entrances, and working independently but we don’t close the weave poles up, they are left open enough that a puppy isn’t twisting.
There are many activities you can train so your agility lessons are more effective and you will be a better competitor. Crate games.... when you and your dog are ready to run courses, your dog will have to be quiet and comfortable stay in a crate while you walk the course. Often clubs have crates in the facility to use so dogs need to be comfortable not only in their crate at home, but strange crates and their travel crate. If your dog isn’t solidly crate trained, you can work on it now. Your dog needs a solid sit stay that will allow you to walk away 10-15 feet in an exciting environment. Watch me games train focus on you. Crate games, sit stay and watch me etc. are activities that you will work on while learning agility. They aren’t requirements to Start training but they are things you will need and can train at home to prepare. It really helps to take a good general obedience class first....you will learn how to train a solid sit stay, watch me, loose leash walking and working in a ring with other handlers and their dogs. I can tell in the first class which dogs have had some obedience training, its easier for the handlers to work with their dog in class.