Too early??

You can certainly try to book vendors but my biggest concern is what would happen if for example your DJ would retire or go out of business. Then you'd have to just find another DJ. I would also hold off on things like asking your bridal party. You won't want to do that until much closer to the actual wedding. Relationships can and do change so asking too early can 100% lead to issues later on. I also wouldn't pick any decor, flowers, clothing, or food or cake. Your prefers could change from now and until then. Honestly I would hold off on most things as that's still almost 3 years away. But I also can't imagine waiting that long.

I would probably wait. Most vendors won’t even let you book them more than one year out. And even if they did, there is a good chance you could change your mind in the years before your wedding, then you would either be stuck with a vendor you no longer want or out your deposit. It sounds like you’re really excited about starting the planning process, so I bet you are going to be looking at a lot of wedding sites, Instagram/Pinterest inspiration, etc. And the more you look, the more ideas you’re going to have, and the more your ideas will change and evolve over time. I would wait until 12-18 months before your wedding date to start making concrete decisions and booking vendors. That doesn’t mean you can’t start doing other things now though! I would set a budget and create a savings account just for the wedding. Check out fun wedding websites, Pinterest, Instagram, etc. to get inspiration. Make a Pinterest board where you can keep all your ideas together and organized - it will make it easier for you to go through everything at once when the time comes to make concrete decisions. I would also start researching vendors (Photographers, videographers, hair and make up artists, etc.) in your area and create a binder of your favorites. It’s super helpful to already have the legwork done and be organized when the time comes to start pulling the trigger on booking vendors.