trying to average groups from a column

Hello,

I have a long column of data and I have to get the average of x rows, and then the next x, and then the next etc. So for example average(A2:A6) and then average(A7:A11), average(A12:A16),...,average(A_n:A_n+4). Is there a way to do this with one command and maybe create a new column with these averaged values? i hope this makes sense D: thank you so much! im really new to excel