What does "go ahead" mean?

Move forward rapidly or act without restraint; also, continue something. For example, If you want to borrow the tractor, go ahead. This expression is often put as go ahead with, as in Are you going ahead with the house party? The term dates from the mid-1600s and gave rise to give the go-ahead, meaning “give permission to move or act in some way.”

go ahead of. Make one's way to the front of, as in They went ahead of me to see the purser. [Mid-1700s]