Continuous vs categorical analysis

I have a logistic multivariable regression model, and I am trying to understand what would happen if I analyze an independent variable, age, as continuous vs categorical, in regards to the width of the CI, and the p value.

My understanding is that if I increase the number of categories (as opposed to continuous), then the standard error will increase, and therefore will decrease the test statistic. Increased standard error will make the CI wider. Is that correct?