Dear princess,
Greetings and welcome to justanswer,
Its good to have the pulse oximeter reading of 100% though the acceptable normal range is 95 - 100%.
It may be seen as 90% or below in some individuals due to some associated lung or heart disease.
Here is the link for more information
pulse oximeter
Let me know if you have any doubt.
Thank you!
Doctor (MD)
M.B.B.S. with four years of experience in the field of Medical practice