I concur. My biggest fear is to go blank in the middle of my talk, and so I minimise the possibility of that happening by over-preparing. I actually write my presentation out and read it verbatim a few times, then rehearse how much I can remember based on using each slide as a prompt with presenter notes hidden, then I do it again a few times by using the "next slide" presenter view as my prompt. I then rehearse my presentation to the cat, a plant, and finally to a couple of trusted colleagues. By the time I get up on stage I've rehearsed the whole bloody thing so many times that it feels like it's a talk I've given several times already, when it's actually the first time.
At least, when I have enough time, that's my ideal preparation. Sometimes I have to skip parts of that process, and luckily I've given enough talks that I can improvise based on experience if required. But for my first talk, that would be my recommended approach!
Good luck! I'll be thinking of you on the day—World IA day is my birthday this year, and I'll be in Wellington attending the festivities there.