Keeping the same five rows for average formula

I’m trying to create a 5 week average formula. However, every formula that I create seems to change by one row when I add in new data for the week. I want the same 5 rows that I originally selected to stay the same even when I add an additional row. I’ve tried adding in the $ sign at various places to keep the row the same, but it does not work. Any suggestions? I’m not sure if I need to add in an index or indirect command into the formula?

Let me try to clarify.

The data in the cells contains weekly website view totals from an analytics report. Each week, I add in an additional row to reflect the week's website views & other analytics. The column that I'm looking at is column B and there is data in the cells from B4 to B110. All I'm trying to do is create a formula for the past 5 weeks which is in B4 to B8. However, when I add in a new week's data, the formula automatically changes to average B5 to B9. Is there anyway to make it so that the formula is always calculating B4 to B8. I don't want the calculation to change even if a row is added. Does this clarify?

All I had before was the basic average formula so =average(b4:b8). I've tried adding in the $ signs to keep it absolute, but it still changes when I add in the row.

This is what I put in: =AVERAGE(INDIRECT('Content USCBC'!B4:'Content USCBC'!B8)) and I got a #ref error. The Content USCBC is the other spread sheet that I'm pulling the data from.

Thank you!! This worked!