First swim meet

Tomorrow morning is my very first swim meet. I'm very nervous but it was time for me to finally see what I could do in competition versus practice. There are so many things that can go wrong like forgetting to exhale well under water, running out of steam during my 100 free, forgetting stoke mechanics, diving too deep, etc. I don't care how i do compared to others, I'm competing with myself. I always imagined my race times would be faster than my practice times and I know i will be very disappointed if that's not the case. Any words of advice on how to mentally approach this wold be greatly appreciated. Like you wet the bed in your first meet but it got better in subsequent meets:D. One other question; how do I control the depth of my dive on entry. I rarely every get to practice dives because our pool doesn't allow dives off the blocks unless with the team/coach. So I can only practice it off the pool edge (my masters team doesn't do much start practice). Should I arch my back on head and trunk entry or angle my hands up? If I dive too deep (I hardly have a superb dolphin kick to compensate), I'm toast. It's pretty much hit or miss with me now. Thanks.