Congrats on entering your first meet. It should be an exciting day. The meet will be long so bring something to eat and a lot to drink. Since you are pretty close the competition I would suggest you just lift raw even if gear is allowed as you won't have time to buy it, practice with it, and use it correctly. For you I would have you work up to your openers on Monday and Tuesday (squats and maybe deads on one day, bench on the other) following by very light assistance stuff the week of the meet, rest fully on Thursday and Friday and I am assuming the comp is on Saturday.
I thing I want to strongly caution you on is to open light, particularly with the squat. I would say this to all new lifters and also from two things you have said I am extra worried about it. At your weight and age it is exceedingly rare that your squat is better than your deadlift, and if you are thinking 405x5 gives you a good shot at 500 then you are probably not estimating your maxes well. Depending on the federation you choose to lift in, the squat must be parallel or often below parallel for it to count. If you want to post a video or see a video I would be happy to watch your squat or point you in the right direction. Based on the numbers you posted, I would suggest you go with the following lifts
Squat open with 365, if it goes well go to 395, if that goes well then 415-425 or so (the more I think about it, your squat is really good for your age which is awesome but also worries me that your depth is not correct, which can make a huge difference. I squatted 405 at 19 yrs at 198 in my first meet and that was pretty good for a teen, not saying you can't do better than me, I just don't want you to do a 3/4 squat and bomb out of your first meet)
Bench (I am assuming you know it is paused with a press command) open with 265, then go 285, then go 305
If you didn't know it was paused take 20 lbs off all attempts, but must stay down and feet must stay flat
Deadlift open with 365, then go 405, then go 425-435
Good luck with it, it is an awesome sport once you get into it, hopefully your first experience is a good one. If you have other questions let me know