The aero difference in a crit depends on how the race goes. Since this will be your first race, you have about a 50% chance of not finishing with the main pack, in which case, no wheel is going to help you.

If you're an all-star and attack solo off the front for an hour, you're maybe looking at 2 Watts for the duration of the break. May not sound like much, but when you're dying at your limit, and someone asks if you'd like 0.7% more power, you'd say "yes."

If you race like most 5s and 4s, you're just screwing around in the pack until the last 100m, when your speed will be much higher when you get your nose in the wind. You might be looking at a 4W difference for the last 50m, which can be the tire-width between 1s and 2nd. It can also be the tire-width between 11th and 12th.

At this point, I'd say to save your money until you've raced. I upgraded to Cat 2 last year riding a 32h 3x 30mm deep front wheel with round spokes (most of my points came on a 10-year-old steel bike). Better wheels would probably have given me a couple better placings in a couple races, but it's not worth it to me. I still won a bunch without the wheels, and with the wheels I still would have lost plenty as well.