Having Serious Doubts

I’ve started my journey to doing 100 consecutive pushups. I am looking at the amount of pushups I have done so far and thinking about how much I’ve struggled. I am now wondering if this is even possible. I went back to the site to make sure I was doing things correctly. I’veĀ  completed day two of week one tonight, and I can’t lift my arms to type. I can feel tiredness and soreness shoot up my arms for every key press as I type. Can anyone in any sort of decent physical shape confirm that it’s supposed to be this hard?