Great app, however
If you can already do, say 15 push-ups in a row you are better off starting at the end of week 2. It should adapt according to a starting fitness test and give more reps from day 1 like some other apps do. Also, I find that the app reminds me to workout on days I have not chosen.
Jayqc about
PushUps for Beginners - 0 to 100+ Pushups Training, v1.3