Thanks for trying racing and hells yes stick with it.
For all but very few a first race is like a swift kick in the teeth. You really don't know how fast it's really going to be or what's required until you do it and learn what will and won't work for you.
As for Cat 5 being fast - yes this is part of the thing that kills competitive cycling for newer racers or racers that will never really be super fast: everyone starts as a 5.... even the next Greg LeMond. The abilities at the line of a cat 5 ...errr... "Novice" race as we call it now, are so varied that it's insane. It's kind of like going to a car race and lining up with a 80's K Car at the same line with a couple of supercars. (Not saying you're the K car but hopefully you get my point). Maybe all you need is a "tuneup" and maybe all you need is experience to anticipate what's going to happen. Only one way to find out...race.
With the fact that there hasn't been much racing there are a ton of people travelling from out of state to go to any race they can. That will always raise the level of competition. Few of those travelling are hacks with no talent (like me).
My advice - be ready for all hell to break loose as soon as the whistle blows. Do whatever it takes to hold wheels. All of this is in the other threads but more fun to take it piece by piece here. The further up you are the easier it is to react. If you're timid an in the back and have a questionable fitness then you're most likely going to get shelled. Give it everything. Then if you get dropped take notes on what the effort felt like and how long it was and think about how to maximize that in the future. Sometimes all it takes is racing those efforts to get the fitness to do them over and over.
You'll find as you move up that races have a natural pace. in the 4's and 4/5's it's usually fast as f right from the gun. Super negative racing - everything that moves gets chased down by someone. Learning to just hold on to when those surges happen is key. Then they just settle down. Everyone kind of realizes nothing is getting away and they just start trying to think of their endgame plan. It never really gets slower but everyone is warmed up and ready to work and no one has any aspirations of trying to get away.
Couple key pieces of advice I like to give newer racers:
1. Look at the course while pre-riding or walk around it. If there is nothing technical (hill, sharp or difficult corner, etc) then nothing is getting away (unless there is a genetic freak that is getting away regardless) and all of the riders who "shouldn't" be there at the final sprint will be there so be careful.
2. The last 2 laps or so the corners will handle completely differently. Everyone picks up the pace and with the adrenaline you get this weird feeling you are going the same speed as you have been but you're going quite a bit faster and the bodies will get carried further into the exit of the corners creating a lot of opportunities for riders to get pinched...get to the inside.
3. You'll find you like to corner on the inside or outside naturally. Do what works for you but be aware of the physics. Cornering on the inside requires more work as you surge more (slow and speed out of the corners) but when the poop hits the fan the physics of the situation push riders to the outside leaving the inside open. Can't tell you the number of times I have watched a wreck start in front of me and just slide out to the outside opening this wide safe opening for me to accelerate into.
4. Have fun.