At this stage, it is only you who will notice there is a change in your body because of how easily and quickly you finish your daily activities. The 37th day of push-ups is not enough to develop your body for another person to notice it. If you are consistent enough and do the push-ups for three months, your body will start developing, and another person will see the physical change in your body.
I get your point. But experts say that 30 days of consecutive work out ( push ups in context here)is enough to cause obvious changes in your body, enough that any one would notice, although standard time for changes in the body due to work out is 2 weeks. It doesn't have to take three months to start 'developing', for example, it doesn't take three months for someone trying to loose weight to start cutting down... Take it from me, I work out a lot, and I've spent my life around that kind of environment. These are muscles were talking about, they expand and contract. Push up does this: stretches your muscles to a point it doesn't revert to it's original size, and that doesn't take three months of consecutive routine to start happening. Infact , somebody who's done 100 push ups for 3 months, that's about 9000 push ups, will definitely not "start developing" if you know what I mean.
Mate, if you work out a lot, you will know that one month is not enough to develop your body. One-month training is a stage to test you to see if you can continue with the push-up because of the pains you go through. After that one month, your body will be used to it and set for development. If it is easy to start developing your body within one month and another person notices it, nobody will quite work out because they are not getting a good result early. And also know that push-ups don't give permanent big muscles; if you stop doing push-ups after gaining big muscles, those muscles will reduce, and you will not like your body the way it is.