Hi, everyone is different, but I waited until both of my kids were exactly 1 year. Heck, your son is 11 months, you only have 1 month to go!!! I always say that they have some "rules" for a reason...but then again, I always take the rules, and then decide if I want to break them, or "tweak" them so to speak, and I decide which ones I want to, and which ones I don't. That was one that I just didn't want too...especially when they say it is about development of child's brain, etc...
But at 11 months, I am sure all will be well surely!!!
Also, just my tip...give them the Whole Milk right out of the frig (cold). My one friend warmed it up, etc., and then always had too or baby wouldn't drink out of it. Both of my kids made the transition from breast to bottle to Whole Cold Milk to 2% Cold Milk fine! I just try to make some things easier for myself, cuz' those darn kids are sooooo stubborn!!!
Whatever you decide will be PERFECT though!
All the best....