You're making a huge assumption in that you'll be able to "push" your car somehow at your very first HPDE.
I'm going to be very blunt with you.
You will not.
In my 10+ years of doing this stuff, I've only EVER come across a student on his very first HPDE to even remotely have been able to push his car close to its limits. And he had an E30 325e (okay, it had an eta block with i headers) with cheap Pep-boys specials ($50 each Fuzions) All-Season tires with 600 UTQG rating. But that's not the reason why he was able to push his "mighty" 325e near its limits. It was because he's been competing in Jr. Karts for years and have been karting even after his Jr. Karting career was over, and this was his first track event with a "car" but he's probably had just as many track events as I had done myself. Needless to say, a beginner he was not.
Outside of that one "outlier" (is that term still being used?) I have not come across anyone capable of pushing any modern BMW equipped with just about any tire under the sun fully to what the car and tire is capable of doing. And the dude with the karting experience in his 20+ year old car (I think at the time the car was the same age as him) riding on crappy all-season probably could have kept up with some intermediate level drivers in their E46 M3s on über summer tires like Michelin PS2s, had it not been Laguna Seca.
You are about 5-8 events too early to worry about what tires to use, in my not so humble opinion.
The hell I don't! LISTEN, KID! I've been hearing that crap ever since I was at UCLA. I'm out there busting my buns every night! Tell your old man to drag Walton and Lanier up and down the court for 48 minutes!