My daughter is 2.5 years old (29 months to be exact) and she's just never been into learning things like that. She's a very physical child and her motor skills have always been more advanced than anything else. She has only recently become interested in singing her ABC's, but doesn't recognize any letters. She sort of counts "1,2,4,5" when she's gearing up to do something like race or jump into the pool. She has just recently started asking about colors, but really only recognizes blue so far.
However, she is doing somersaults, running backwards, climbing her rock wall with no assistance, almost totally potty trained, etc. She's just a more physical kid and prefers to master her motor skills before anything else. I really don't worry about it, personally. I expose her just like any other kid, she's just not into it yet. I have a daycare kid one month older than her who is counting to 10, recognizes almost all the colors of the rainbows, knows her ABC's and recognizes the letters in her name. The trade off is that she's not nearly as advanced physically and those two have always been that way.