Is it really true that in a skeletal formula it doesn't matter what end you count C1 from when attaching ....

a functional group? That's what my teacher said but I don't trust her and it doesn't say anything specific in the text book.

/\/\/\/ E.g would it matter if I put methyl ( I ) on either end starting the count of Carbon atoms from the left or right to make 2-methyloctane?

This is an octane based molecule. So start counting the carbons in octane from the left side