Surely there is no need to kick yourself or even to put undue pressure on yourself to do something like 100 pushups per day, especially if you may well have either a lot of other physical activities (including  exercises that you do) and/or if you might have a schedule/routine that is not very conducive to fitting in 100 pushups per day (& every day).  

Frequently, my five sets per day feels really grueling, even though I am able to fit such a thing into my schedule, and I am allowing myself (or authorizing myself) to create such a priority to do that many pushup sets per day.  So out of my 253 days of doing pushups, I have right around 70% of the days that I had done 5 or more pushup sets for those days.

I am tentatively thinking that once we go over $100k. . if we go over $100k, then maybe at that point, I will cut back on the number of pushup sets per day, even though there seems to be a certain value in doing pushup sets in order to be able to continue to be able to do them, so there is a risk for any of us that our abilities to do pushups is likely going to go down once we stop or slow down doing pushups, so we would have to build back up to being able to do them in the event that we cut back in the quantity of pushups that we do per day.

Losing endurance becomes more likely to happen the older that we get, so sometimes if we might be an older person, it might take us longer to build up to a certain high level of endurance as compared to a younger person, and it also might take us a bit longer to build up our recovery times, so that we are not as sore between our exercise sessions, whether referring to pushups or other kind of regular exercise that we might end up doing.