we held back our boys a extra year and it has helped them out greatly ( they go to Preschool at the same school they will go for kindergarten). Our primary reason for holding our back was speech and maturity level.
lol at poorly done photoshop
http://www.jeep.com/shared/2012/wrangler/gallery/images/capability/towing/tertiary/10_j_w2d_cap_tow_award_ter.jpg
and honestly the trailer in that image weights about as much as that CJ.