What is the average amount of time it takes a salior to make Senior Chief in the Navy?

A simple google search indicate the average time to make Chief is 13 years, and 17-20 to make senior chief

It depends on how the person got into the Navy. If they started out as an E-1 and got advanced the first time, every time, he could be an E-8 in 12 years. That is just going by the time in rate numbers. It can be a shorter time to making it if there are certain things that happen earlier in their enlistment. Things like automatic advancement out of boot camp and/or A school. Being able to take the advancement exams one cycle early due to excellent performance annotated on their evals is another way to shorten the time. There is also the chance that they never make E-8 and they are forced to get out or retire due to high year tenure. It all depends.

There is the Navy wide average, which has been indicated by SSG Dickhoff. But, realistically, it will depend on your rating, and on you (billet choices, evals, education, sustained superior performance, Sailorization, etc.). Good luck.

Oh, and Sailor is capitalized.