For what it's worth, you'll be slower on the next climb, but you will complete it and the rest of the event. You'll recover some on the descent and approach to the second climb. You might want to be sure you're not going too deep on the first climb so you're not more fatigued than you need to be the rest of the ride. That second climb might be steeper though shorter. Look at something like Strava to see what other cyclists did on those climbs last year.
And you'll get stronger over the next month as you focus on climbing, before you taper the last couple of weeks.