How can you get the first enemy on a track? (FIXED PROBLEM)

I am developing a tower defense style game. When the towers shoot, they shoot at random enemies in range, and it doesn't get the one that's closest to the end. I have tried if functions and it still doesn't get the first one. The code below gets an enemy in range that exists. However, it always shoots the enemy that is the farthest away from the end when in fact I want the opposite.

local closestpart
		for n,e in pairs(workspace.Game.Enemies:GetChildren()) do
			if e ~= nil then
				local mag = (tower.PrimaryPart.Position-e.PrimaryPart.Position).magnitude
				if mag <= script.Parent.Range.Value then
					closestpart = e
				end
			end
		end

I have a source value, which says where it is on the map, but I cant seem to find out how to get that to make the towers ALWAYS shoot the first enemy that is in range.

local closestpart

while true do
	for n,e in pairs(workspace.Game.Enemies:GetChildren()) do 
		if e~= nil then
			local mag = (tower.PrimaryPart.Position-e.PrimaryPart.Position).magnitude
				if mag <= script.Parent.Range.Value then
					closestpart = e
				end
			end
		end
	end