Buy the Trek. Ride it all the time. Maintain it properly, keep the drivetrain clean and the brakes adjusted optimally. When, after thousands of miles, something begins to wear beyond what can be cleaned and adjusted, replace. The order that things will need replacing due to wear will be: chain, cables, brake pads, handlebar tape (in there somewhere), [repeat], then someday shifters. If you crash, all bets are off.

Bottom line, there's no need to replace any component before it fails. If your abilities increase to the point that shifter/derailleur performance really matters, then progressed beyond where that bike'll take you. Worry about it then...

Good luck!
Phil