Some brief observations:
- Your ready-variable is not used; the games starts even if the user is no ready. Not so much an issue with the design of the program from a coding point of view, but it is a surprise for the user.
- The success-variable is not necessary. It is only true when position is 's', so use that as a break condition.
- A quit option would be nice to break the game. Perhaps not so much in this particular case since the game is short enough to end within just a few moves on average, but in general you should consider it.
- You may want to move the win condition to after the loop instead. This can be argued though, since it depends on what you consider game loop logic. The win condition is not part of the loop but as a part of the exit condition, but on the other hand it is also a part of the set of valid inputs during the game.
- A final else-statement taking care of invalid input would be nice so the user knows the input was invalid instead of wondering why the computer guessed the same number.