Move the commented out lines at the top that turn the heaters on to below the probing, and uncomment them. That way you'll have control over where the heating starts. Otherwise, like RJ says, Cura (or the much more configurable slic3r) will turn the heaters on for you by adding lines before your startup code.
However, the extruder and bed will expand slightly (remember we're dealing in tenths of a mm, or smaller) and give you less accurate results A better method is to retract your filament after it heats up and before you probe, such as when you finish your previous print. For example, add this to your end gcode:
G28 X0 ; move to the far left
G91 ; relative positioning
G1 Z10 ; move extruder position up a little
G1 E-0.5 ; retract a half mm, increase if necessary
Untested, so you might need to tweak it a bit. This will move your extruder off to the side (remove G28 X0 if you've set a park position, I don't use Cura). Next tell it to move relative to where it is, instead of relative to zero. This gets the hot stuff out of the way. Then suck the filament back a bit, the actual length will be hot end and extruder dependent. Add this before any code that turns off the extruder heater, if you can, although it won't cool off fast enough to go to cold extrusion prevented,
I'd test it, but we're about to leave for the airport to pick up the youngest moosette, who's giving a talk on entrepreneurism tomorrow at the local engineering U.
Modified KickStarter Classic Plus 7/2012
KS Thingybot Delta Pro 10/31/16