I did it! Despite being extra challenged due to attending my brother's wedding reception last night, I finished the challenge strong. I reversed the order of the exercises (plank, push-ups, sit-ups) and was able to complete all of them.
Who knows, I might just keep this up over the next month. It doesn't take that much time and I feel it does make a difference. Maybe I'll switch out the sit-ups for something like lunges or squats so I'm working another muscle group.
Let's get rid of some stuff! I'm going to get rid of seven things a day for seven days. Stay tuned...