I can't see the video, but I agree, beginner novice is a good place to start, it's pretty straightforward and shouldn't have any major questions. Check if you need qualifying scores to move up, I know we do in Canada, not sure about the states though. It's good to get established and super confident at a level before moving up, and it keeps people from entering levels all willy-nilly too, thinking because they're jumping 3'6" at home they can just go enter one event a year at training level, and of course THAT was always a train wreck
That happened a lot back before they added the qualifying scores at the lower levels.
Since this is your first actual even I would try find an eventing trainer to help you out, even just at the event if you can, many will take on students just for the day or weekend if you ask around. A real event is a lot different than schooling shows. I had shown a good amount before I started eventing, but I was SO GLAD to have a coach with me who knew what was going on my first few events, because just the way things are run, different rules, scheduling, etiquette, it's VERY different from a regular horse show. And I started out at the baby levels too, it never hurts to have that knowledgeable person around! Also very helpful to have an extra set of eyes for walking your cross country course!
Have you schooled much cross country before? In beginner novice you may have to cross through water and may have a small bank or ditch, make sure you have properly prepared your horse for anything they may see. Are you familiar with the cross country speed for the level? You definitely don't want to just go and wing it, that rarely ends well. There's lots of homework that needs to be done before you head out to an actual event.
There's a lot to be said for just taking things slow with eventing. There is definitely no rush to move up, and if after a couple events at BN, you're rocking it out and ending on your dressage score, and schooling novice heights and fences, then by all means move up! And if you and your horse are still working some kinks out, no worries! Sometimes things can take a while, but if you work hard, and are dedicated to preparing properly, I have no doubt that you'll do well! And listen to your body and your horse, it's best to go a little slower at first, than to push everything and end up on the ground or scaring your horse, that takes a lot longer to undo in the long run!
My best advice would be to find someone knowledgeable to school cross country with at least a few times and help you out at shows/events and make sure you are well prepared for all 3 phases (beginner novice dressage definitely requires both canter leads). If you do that, your first event should be super fun and easy!